ICTON 2017 - Invited abstracts Print E-mail
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19th International Conference on
Transparent Optical Networks ICTON 2017
9th Sub-Wavelength Photonics Conference SWP 2017

Girona, Spain, July 2-6, 2017



Preliminary list of Invited presentations shown by conference session:
ESPC – 16th European Symposium on Photonic Crystals
WAOR – 16th Workshop on All-Optical Routing
GOWN – 14th Global Optical & Wireless Networking Seminar
RONEXT – 13th Reliability Issues in Next Generation Optical Networks Workshop
PICAW – 13th Photonic Integrated Components & Applications Workshop
OWW – 13th Optical Wireless Workshop
NAON – 12th Nanophotonics for All-Optical Networking Workshop
PAM – 12th Special Session on Photonic Atoms & Molecules
Novel Glasses – 11th Special Session on Novel Glasses for photonic devices
MARS – 10th Anniversary Special Session on Market in Telecommunications
ACCESS – 9th Workshop on Broadband Access
SWP – 9th Sub-Wavelength Photonics Conference
CTS – 8th Workshop on Communication in Transportation Systems
GOC – 7th Workshop on Green Optical Communications
MWP – 7th Special Session on Microwave Photonics
BigNeO – 4th Workshop on Big Data Analytics and Network Optimization
DACINT – 3rd Workshop on Technology for Data Center Interconnects
DCN – 3rd Workshop on Datacenter Networks
5GT – 3rd Workshop on 5G Transport Networks
FiWiN5G – 2nd Workshop on Fiber-Wireless Network Technologies and Architectures towards 5G and Beyond
QPhot – 2nd Workshop on Quantum Photonics
NetOrch – 2nd Workshop on Multi-Layer Network Orchestration
NOA – 1st Workshop on Novel Optical Amplifiers
Flex-ON – 1st Workshop on Flexible and High-Capacity Optical Networks
LFSR – 1st Workshop on Label-Free Super-Resolution
EU-P – EU-Project Session

ICTON invited presentations: 

Olivier Alibart
All-optical synchronization for quantum communication networks
B. Fedrici, L.A. Ngah, O. Alibart, F. Kaiser, L. Labonté, V. D’Auria, and S. Tanzilli
Université Côte d'Azur, CNRS, Institut de Physique de Nice, France

Tiago Alves
Adaptive loading with extended memory to relax the impact of the phase noise-impaired ICXT in DD-OFDM MCF-based systems
T.M.F. Alves1, A.V.T. Cartaxo1,2, R.S. Luís3, B.J. Puttnam3, Y. Awaji3, and N. Wada3
1Instituto de Telecomunicações, Instituto Superior Técnico, Lisbon, Portugal
2ISCTE - Instituto Universitário de Lisboa, Portugal, Lisbon, Portugal
3Photonic Network System Laboratory, NICT, Tokyo, Japan

The impact of the laser phase noise on the intercore crosstalk (ICXT) of orthogonal frequency division multiplexing (OFDM) multicore fiber (MCF) based systems employing direct detection (DD) is experimentally investigated. Random fluctuations of the ICXT and system performance induced by the laser phase noise are observed in both time and frequency. The origin of these fluctuations is the random phase mismatch of the photodetected ICXT that results from the beating between signals originating from different cores and generated by two independent laser sources. Adaptive bit loading employing extended time memory is proposed and demonstrated experimentally as a possible approach to counteract the large performance variation of the DD-OFDM MCF systems induced by laser phase noise and ICXT.

Tibor Berceli
Distortion cancellation for solitons carrying high speed information in WDM systems
N. Badraoui1,2, T. Berceli1, and S. Singh3
1Broadband Infocommunications and Electromagnetics Department, Budapest University of Technology and Economics, Budapest, Hungary
2Formerly University 8 May, Guelma, Algeria
3Department of ECE, Sant Longowal Institute of Engineering and Technology, Longowal, Sangrur, Punjab, India

The wavelength division multiplexing (WDM) type optical communication significantly increases the transmission capacity. However, one of the key issues is how we can reduce the pulse broadening and the interaction between the neighboring channels due to the nonlinear effects. The optical soliton offers the answer to this question. The soliton pulse can keep its shape during propagation, when there is a proper balance between the second order dispersion effect and the nonlinear Kerr effect, the main physical effects influencing the soliton propagation in optical fibers. Using the soliton approach, the pulse power has to be high enough to utilize the fiber non-linearity for keeping the pulse shape but its power has to be small enough to avoid the generation of higher order solitons. Simulations confirm our theoretical hypothesis for the design principles of soliton transmission in WDM systems. Due to new online filtering processes, soliton systems can now provide their benefits.

Sonia Boscolo
Pulsating solitons in mode-locked fibre lasers
Junsong Peng1, S. Boscolo2, N. Tarasov2, S. Sugavanam2, D.V. Churkin3, and C. Finot4
1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
2Aston Institute of Photonic Technologies, Aston University, Birmingham, UK
3Novosibirsk State University, Russia
4Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS – Université de Bourgogne Franche-Comté, Dijon, France

We report on our direct experimental observation of new regimes of operation of passively mode-locked fibre lasers where the laser oscillator generates pulsating solitons with extreme ratios of maximal to minimal intensities in each period of pulsation. The soliton spectra also experience large periodic breathing and compression. Dispersive Fourier transformation and spatio-temporal intensity measurements enable us to capture such transient dynamics in real time. Our numerical simulations of the laser confirm the experiments and provide additional insight into this exotic phenomenon.

Hans Brunner
A low-complexity heterodyne CV-QKD architecture
H.H. Brunner, L.C. Comandar, F. Karinou, S. Bettelli, D. Hillerkuss, F. Fung, Dawei Wang, S. Mikroulis, Qian Yi, M. Kuschnerov, A. Poppe, Changsong Xie, and M. Peev
Huawei Technologies Düsseldorf GmbH, Munich, Germany

In contrast to the more prominent discrete-variable quantum key distribution (DV-QKD), which requires specialized hardware like single-photon detectors, the continuous-variable version (CV-QKD) promises low-cost and high-performance implementations by leveraging mature telecommunication technology.  In this paper we demonstrate a simplified CV-QKD architecture based on analog frontends and digitizers for mobile communication systems and standard optical components. The high-fidelity, software-defined receiver and transmitter allow us to shift complexity from the analog to the digital domain, thus simplifying the system, improving robustness and paving the way for a low-cost implementation.

Adolfo Cartaxo
DD-OFDM multicore fiber systems impaired by intercore crosstalk and laser phase noise
A.V.T. Cartaxo1,2, T.M. F. Alves1, B.J. Puttnam3, R.S. Luís3, Y. Awaji3, and N. Wada3
1Instituto de Telecomunicações, Instituto Superior Técnico, Lisbon, Portugal
2ISCTE - Instituto Universitário de Lisboa, Portugal, Lisbon, Portugal
3Photonic Network System Laboratory, NICT, Tokyo, Japan
The photodetected intercore crosstalk (ICXT) of multicore fiber (MCF) based systems employing direct-detection (DD) is characterised. The impact of the laser phase noise on the photodetected ICXT and on the performance of DD orthogonal frequency division multiplexing (OFDM) MCF-based systems is experimentally demonstrated.

Christophe Caucheteur
Optical power-based interrogation of near-infrared fiber grating spectral combs
Á. González Vila and C. Caucheteur
Electromagnetism and Telecommunication Department, University of Mons, Belgium

Near-infrared fibre grating spectral combs provide a platform to measure tiny refractive index variations in the medium around an optical fibre, which has led to the development of a wide variety of sensors. Their interrogation is usually carried out by means of a spectral analysis, but simpler and more efficient techniques become really attractive for practical applications. This work reports two configurations based on the use of a broadband optical source and a photodiode as a detector, resulting very competitive in terms of cost-effective operation. They both exhibit a sensitivity value high enough to be considered as worthwhile alternatives.

Luca Chiaraviglio
A measurement-based analysis of temperature variations introduced by power management on commodity hardware
L. Chiaraviglio1,2, N. Blefari-Melazzi1,2, C. Canali3, F. Cuomo4, R. Lancellotti3, and M. Shojafar2
1Department of Eletronic Engineering, University of Rome Tor Vergata, Italy
2CNIT, Italy
3Department of Engineering Enzo Ferrari, University of Modena and Reggio Emilia, Italy
4DIET Department, University of Rome Sapienza, Italy

Commodity HardWare (CHW) is currently used in the Internet to deploy large data centers or small computing nodes. Moreover, CHW will be also used to deploy future telecommunication networks, thanks to the adoption of the forthcoming network softwarization paradigm. In this context, CHW machines can be put in Active Mode (AM) or in Sleep Mode (SM) several times per day, based on the traffic requirements from users. However, the transitions between the power states may introduce fatigue effects, which may increase the CHW maintenance costs. In this paper, we perform a measurement campaign of a CHW machine subject to power state changes introduced by SM. Our results show that the temperature change due to power state transitions is not negligible, and that the abrupt stopping of the fans on hot components (such as the CPU) tends to spread the heat over the other components of the CHW machine. In addition, we also show that the CHW failure rate is reduced by a factor of 5 when the number of transitions between AM and SM states is more than 20 per day and the SM duration is around 800 [s].

Kostas Christodoulopoulos
Improving QoT estimation accuracy through active monitoring
I. Sartzetakis, K. Christodoulopoulos, and E. Varvarigos
Computer Technology Institute “Diofantus” and University of Patras, Greece

Estimating the Quality of Transmission (QoT) of lightpaths is crucial for reducing provisioned margins, making optimized dynamic decisions, and localizing failures. We leverage a QoT estimation tool that uses feedback from the network in order to provide accurate QoT estimations. We propose a scheme to establish active monitoring lightpaths (i.e., probe lightpaths used only for monitoring purposes) in order to improve the QoT estimation accuracy.

Gabriella Cincotti
Design of geometric phase holograms with arbitrary polarization states and waveforms
G. Cincotti , Engineering Department, University Roma Tre, Italy

We furnish a general procedure for the geometric phase hologram (GPH) design, starting from the desired output phase profile and polarization states, and extending the theory of polarization gratings (PG) to arbitrary phase profiles. As an example, we consider the case of liquid crystal (LC) devices.

Jaume Comellas
Quantifying dynamic traffic in elastic optical networks
J. Comellas, L. Vicario, and G. Junyent
Optical Communications Research Group (GCO), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
This work is focused on the characterization of the traffic allocated in Elastic Optical backbone networks when different dynamic traffic profiles are generated. Extensive simulations are done to statistically model the real-time traffic carried by this kind of networks. Well known topologies such as NSFnet and US_Backbone are considered as well as different parameters applied to the traffic generation. Some interesting conclusions are extracted about the properties of the traffic supported by Elastic Optical Networks under dynamic conditions.

Camille Delezoide
On the performance prediction of optical transmission systems in presence of filtering
C. Delezoide, P. Ramantanis, and P. Layec
Nokia Bell Labs Paris-Saclay, Nozay, France

We investigate the impact of optical filtering from routing nodes in optical networks, and how to predict it. From measurements in presence of tight optical filtering, we propose a new method relying on an extended back-to-back model for improved prediction of the quality of transmission.

Antonio Díez
A new technique for the measurement of the nonlinear refractive index in optical fibers
E. Rivera-Pérez, A. Carrascosa, A. Díez, E.P. Alcusa-Sáez, and M.V. Andrés
Departamento de Física Aplicada y Electromagnetismo-ICMUV, Burjassot, Spain

In the last years, acousto-optic (AO) interaction has been proved to be a powerful and highly sensitive method for the characterization of optical fibers. The key of the technique relies on the high sensitivity of the AO phase-matching condition with the structural and material properties of the fiber, enabling the detection of sub-nanometer fiber radius variations, or core refractive index variations in the order of 10−8 in single-mode fibers. In this contribution, we present our results on the use of in-fiber AO interaction for the measurement of the nonlinear refractive index in single-mode optical fibers.

Ivan Djordjevic
FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems
I.B. Djordjevic and Ding Zou
University of Arizona, Department of Electrical and Computer Engineering, Tucson, USA
In this invited paper, we describe a rate-adaptive FEC scheme based on LDPC codes together with its software reconfigurable unified FPGA architecture. By FPGA emulation, we demonstrate that this class of rate-adaptive LDPC codes based on shortening with an overhead from 25% to 42.9% provides a coding gain ranging from 13.08 dB to 14.28 dB at a post-FEC BER of 10-15 for BPSK transmission. In addition, the proposed rate-adaptive LDPC coding combined with higher-order modulations have been demonstrated including QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM, which covers a wide range of signal-to-noise ratios. Furthermore, we apply the unequal error protection by employing different LDPC codes on different bits in 16-QAM and 64-QAM, which results in additional 0.5 dB gain compared to conventional LDPC coded modulation with the same code rate of corresponding LDPC code.

Octavia Dobre
Fifth-order Volterra-based equalizer for fiber nonlinearity compensation in Nyquist WDM superchannel system
A. Amari, O.A. Dobre, and R. Venkatesan
Memorial University, St. John's, Canada

In the context of long-haul Nyquist wavelength division multiplexed (WDM) superchannel system, a fifth-order Volterra-based nonlinear equalizer (VNLE) is proposed to compensate for the optical fiber nonlinear effects, which represent the major fiber impairment in such high data rate system. A performance comparison of the fifth-order VNLE with the benchmark digital-back propagation (DBP) and the third-order VNLE is provided. We show that the fifth-order VNLE combat better the fiber nonlinearity in comparison with the third-order VLNE and exhibits closer performance to the DBP.  A significant increase of the performance in terms of the Q factor, nonlinear tolerance and transmission reach is observed when compared with the third-order VNLE.

Nicolas Fontaine
Amplifiers and wavelength switching devices for space-division multiplexed systems
N.K. Fontaine, Bell Laboratories, Nokia, Holmdel, USA
Space-division multiplexed (SDM) systems use multiple spatial-paths in multimode or multi-core fiber to increase the capacity and/or photon-efficiency carried by an optical fiber. For SDM systems to be competitive, they must outperform or have a cost advantage over parallel single mode fiber systems. The cost advantages can come from spatial integration where many spatial channels can be processed by a single device. We will show enabling components such as wavelength-selective switches and optical amplifiers for various types of multimode fiber.

Ivan Glesk
Management of OCDMA auto-correlation function distorted by dispersion effects
M.S. Ahmed, M. Abuhelala, and I. Glesk
Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, UK

Dispersion has very strong detrimental effects on high data rate incoherent transmission systems. Situation gets much worse when data bits become just a few picoseconds long. In this paper we investigate how the dispersion can affect an Optical CDMA auto-correlation function when data are carried by two-dimensional wavelength-hopping time-spreading codes based on picosecond multi-wavelengths pulses. We will show how chromatic dispersion changes and changes of optical fiber temperature can both distort the OCDMA auto-correlation. Then we will demonstrate a simple method how to mitigate both of these effects.

Norbert Hanik
A memory polynomial based adaptive digital pre-distorter for optical communication transmitters
G. Khanna1, B. Spinnler2, S. Calabrò2, E. De Man2, U. Feiste2, T. Drenski3, and N. Hanik1
1Institute for Communications Engineering, Technical University of Munich, Germany
2Coriant R&D GmbH, Munich, Germany
3Socionext Europe GmbH, UK

We present a robust adaptive digital pre-distortion technique to mitigate the linear and non-linear degradation of optical communication transmitter components. The proposed method is based on the principles of memory polynomial based pre-distortion and indirect learning architecture. Effectiveness of the presented algorithm is assessed across various higher order modulation formats and higher baud rates. Significant gains are reported in back-to-back measurements and various lab and field trial experiments.

Gabriel Junyent
Using dual-path allocation for partial traffic protection in elastic optical networks
G. Junyent and J. Comellas
Optical Communications Research Group (GCO), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain

Multi-path allocation has been proposed as a simple way to achieve traffic protection in different networking domains. In this work dual-path allocation is proposed for Elastic Optical Networks (EON) assuming dynamic offered traffic, and its performance is quantified by means of extensive simulations. Indeed, dual-path allocation is compared with partial dedicated path protection assuming different scenarios. In addition to a qualitative comparison where main advantages and drawbacks of both schemes are analyzed, quantitative results for different backbone network scenarios are presented.

Joseph Kahn
Optical MIMO signal processing for direct-detection mode-division multiplexing
K. Choutagunta1, S.Ö. Arik2, M. Moradshahi1, and J.M. Kahn1
1E.L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, USA
2Baidu Silicon Valley Artificial Intelligence Lab, Sunnyvale, USA

Adaptive optical multi-input multi-output (MIMO) signal processing is employed to compensate for intermodal coupling in short-reach direct-detection mode-division multiplexing systems. Complexity is minimized by cascading two stages of fundamentally lossless devices. All modes are first separated by a fixed demultiplexer, such as a mode-selective photonic lantern or multi-plane converter. Coupling within different mode groups is then compensated independently using adaptive 2×2 or 4×4 MIMO processing in Mach-Zehnder arrays. Adapting these MIMO arrays requires a non-standard algorithm. Convex optimization-based phase retrieval converges very rapidly, but requires high-speed analog-digital conversion (ADC). Self-configuration does not require ADC, but converges more slowly.

Igor Koltchanov
GPU-assisted simulations of SDM systems
A. Uvarov1, N. Karelin1, I. Koltchanov2, A. Richter2, H. Louchet2, and G. Shkred1
1VPI Development Center, Minsk, Belarus
2VPIphotonics GmbH, Berlin, Germany

Spatial-Division Multiplexing (SDM) technology aims to overcome capacity limits of single-mode transmission links. Design and characterization of such ultra-high capacity systems requires numerical techniques capable of dealing with vast amounts of data simulating nonlinear transmission and interaction of signals propagating in numerous spatial channels at different wavelengths, thus imposing serious challenges with respect to both, memory requirements and computation performance. We discuss how massive-parallel computation capabilities of modern Graphical Processing Units (GPUs) can be utilized to develop efficient numerical algorithms and present assessment results for the GPU-assisted SDM-capable implementation in the existing simulation environment of VPItransmissionMaker Optical Systems.

Tsuyoshi Konishi
Measurement of mode-locking process using optical pulse ruler
T. Konishi, Y. Yamasaki, M. Hiraoka, and T. Nagashima
Osaka University, Japan

We report measurement of mode-locking process using optical pulse ruler.  It can provide an approachable optical pulse measurement tool like a litmus paper for pH measurement in a liquid solution.

Pandelis Kourtessis
QoE based holistic traffic engineering in SDN enabled heterogeneous transport networks
M. Robinson1, M. Milosavljevic1, P. Kourtessis1, S. Fisher2, G.P. Stafford2, J. Treiber2, M.J. Burrell2, and J.M. Senior1
1School of Engineering and Technology, University of Hertfordshire, Hatfield, UK
2Global Invacom Limited, Stevenage, UK

Due to the variability of network topologies and services that can be deployed in the transport network, traffic engineering decisions within a software defined networking (SDN) controller need to be influenced by the current network topology, available resources, and end user experience.  In this work a holistically approached traffic engineering quality of experience (QoE) feedback application is demonstrated, built on top of a real SDN transport network for heterogeneous optical, 5G and satellite services. This QoE feedback application is split across the SDN controller and client machines, and is shown to provide improvements to end user experience in high load scenarios tested in this paper for multicast SatIP video applications. The proposed solution can also combine unicast, internet streamed and mobile applications.

Samir Lamrini
Recent progress in high-power, high-energy 2 µm lasers
S. Lamrini, LISA Laser Products OHG, Katlenburg-Lindau, Germany

Hans Limberger
Thermal decay of laser induced refractive index changes in SMF-28 and Bi-doped silicate laser fibres
H.G. Limberger1, G. Violakis1, and V. Mashinsky2
1Ecole Polytechnique Fédéral de Lausanne, Switzerland
2Fiber Optics Research Center of the Russian Academy of Sciences, Moscow, Russia

Optical fibre components that are based on laser induced refractive index changes may show changes in their performance during their lifetime, since the underlying physical processes responsible for the refractive index change are more or less stable over time. The stability of refractive index changes depends on the optical fibre and the irradiation conditions. We show that it is possible to denote fibre or material parameters responsible for the refractive index stability using high and low power UV laser irradiation, accelerated annealing tests, and a decomposition of the characteristic annealing function (master curve) into individual activation energy spectra (AES). The SMF-28 fibre exhibits four different AES, indicating different underlying physical mechanisms. Their contribution to the annealing depends on the laser intensity. The bismuth doped fibres exhibit 3 different AES. Their contribution to the total characteristic function depends also on laser intensity and in addition to active dopant concentration. Comparing GeO2-SiO2 fibre with Bi-Al2O3-SiO2 fibres, activation energy spectra are attributed to glass species or dopants.

Manuel López-Amo
Random fiber lasers: Application to fiber optic sensors networks
M. López-Amo, D. Leandro, V. de Miguel, M. Bravo, M. Fernández-Vallejo, S. Rota, and R.A. Pérez-Herrera
University of Navarra and Institute of Smart Cities, Pamplona, Spain

Recently, random mirrors have been proposed as a method to create fiber laser cavities. This kind of cavity is based on cooperative Rayleigh scattering, which is generated along a fiber due to the material inhomogeneities presented in that fiber. In this work, basics of Random fiber lasers and different demonstrated lasing sensors systems for interrogating arrays of optical fiber sensors are shown. These systems use different kinds of amplification and cavities schemes and can interrogate optical fiber sensors located up to 225 km away.

Uri Mahlab
Entropy-based load-balancing for software-defined elastic optical networks
U. Mahlab, P.E. Omiyi, H. Hundert, Y. Wolbrum, O. Elimelech, I. Aharon, K. Shishchenko, and S. Zarakovsky
Holon Institute of Technology (HIT), Holon, Israel

To support emerging traffic demands, metro optical networks evolve over time with the addition of new links to relieve network bottlenecks and congestion. These new resources need to be optimally located in the network, in order to minimize the cost of the new deployment. Spectrum-fragmentation and network-wide load imbalance impede the optimal allocation of network resources. With the recent convergence of advanced flexible and programmable optical devices with emerging software-defined network paradigms, it is possible to flexibly and dynamically defragment the spectrum and balance the load on the network. This study introduces an optimization strategy for software-defined elastic optical networks for fiber-load balancing across the network, while minimizing the cost of the resulting service disruption. An entropy-based metric is proposed for measuring load imbalance and used to design utility functions for the joint optimization, taking into consideration the optical and defragmentation constraints.

Paolo Martelli
Impact of the crosstalk in space-division multiplexing
P. Martelli, Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, PoliCom Lab, Italy
In this work the penalties induced by the crosstalk in case of optical networks exploiting space-division multiplexing and coherent detection are evaluated. Different QAM modulation formats are considered.

Darli Mello
Sub-band-based transmission for mode-multiplexed optical systems
L.F. dos Santos1, F.M. Ferreira2, D.A.A. Mello1
1School of Electrical and Computer Engineering, State University of Campinas (UNICAMP), Brazil
2Aston Institute of Photonic Technologies, Aston University, Birmingham, UK

Mode-multiplexed optical transmission is subject to mode  coupling and potentially large differential mode delays. In most recent  implementations, these effects are compensated for at the receiver by  complex adaptive MIMO equalizers. Although frequency domain MIMO  equalization requires a moderate complexity compared to time-domain  equalization, the long required  FFTs may face implementation issues and yield a relatively slow response to dynamic effects. In this paper we evaluate an alternate transceiver architecture based on sub-band partitioning, implemented by filter banks, which enables concurrent time-domain equalization. The performance of sub-band and single-carrier schemes are compared using Monte-Carlo simulations.

Nelson Muga
Advanced digital signal processing techniques based on Stokes space analysis for high-capacity coherent optical systems
N.J. Muga1,2,3, G.M. Fernandes1,2, S. Ziaie1,2, R.M.F. Ferreira1,2, A. Shahpari1,2, A.L. Teixeira1,2, and A.N. Pinto1,2
1Instituto de Telecomunicações, Campus de Santiago, Aveiro, Portugal
2Department of Electronics, Telecommunications, and Informatics, University of Aveiro, Portugal
3i3N Aveiro, Campus de Santiago, Aveiro, Portugal

Stokes space based digital signal processing (DSP) techniques can improve polarization demultiplexing, polarization dependent losses compensation, and other polarization related tasks in coherent receivers, particularly in terms of convergence speed and transparency to higher-level M-ary signals. This paper reports recent advances on Stokes space based DSP for coherent optical communications. We study and discuss the performance of a new space-demultiplexing algorithm based on signal analysis in higher-order Poincaré spheres for spatial division multiplexing transmission systems. Moreover, practical issues regarding the real-time implementation on FPGAs of Stokes space based algorithms for flexible optical communications are also investigated and discussed.

Alioune Niang
Dynamics of dissipative soliton resonance square pulses in fiber lasers
A. Niang1, G. Semaan1, F. Ben Braham1,2, M. Salhi1, and F. Sanchez1
1Laboratoire de Photonique d’Angers, Université d’Angers, France
2Ecole Polytechnique de Tunisie, Université de Carthage, Tunisia

In this article, we experimentally investigate the dynamics of dissipative soliton resonance (DSR) square pulses in different all-anomalous passively mode-locked double-clad Er:Yb fiber laser setups. In the figure-of-eight configuration, the aim of employing an amplifier in each loop is to control the output pulse’s amplitude and width, which depend on the pumping power. At a maximum total pumping power of 4.7 W and a fundamental frequency of 133 kHz, 10 µJ DSR square pulses with a signal-to-noise ratio of 60 dB, are generated without observing any wave-breaking. In the fiber ring configuration, by fixing the pumping power to 1.18 W and carefully adjusting the polarization controllers, we obtain a DSR square pulse that can be split in a series of equally spaced smaller square pulses up to the 4th harmonic order at a fundamental frequency of 672 kHz.

Eiji Oki
Performance of elastic optical network with allowable spectrum conversion at intermediate switches
N. Kitsuwan1, P. Pavarangkoon1, B.C. Chatterjee2, and E. Oki3
1Department of Computer and Network Engineering, The University of Electro-Communications, Tokyo, Japan
2Indraprastha Institute of Information Technology, New Delhi, India
3Kyoto University, Kyoto, Japan

This paper evaluates the performances of elastic optical networks (EONs) in terms of request blocking probability with and without incorporation of spectrum conversions at intermediate switches. In EONs, dynamically setting up and tearing down of lightpath connections generate spectrum fragmentation problems. The spectrum fragmentation problem occurs when the available spectrum slots are isolated from each other as neither they are aligned along the routing path nor they are contiguous in the spectrum domain. The spectrum conversion at intermediate switches is performed for blocked requests without triggering any defragmentation process. Simulation results indicate that the incorporation of spectrum conversions significantly suppresses the request blocking probability and increases the traffic admissibility when the traffic load is low. In a congested network under heavy traffic load, the performance is comparable with and without incorporation of spectrum conversion.

João Pedro
ROADM express layer design strategies for scalable and cost-effective multi-fibre DWDM networks
J. Pedro1,2 and S. Pato1,3
1Coriant Portugal, and Instituto de Telecomunicações, Instituto Superior Técnico, Amadora, Portugal
2Instituto de Telecomunicações, Instituto Superior Técnico, Lisboa, Portugal
3Instituto de Telecomunicações, DEEC, Universidade de Coimbra, Portugal

The usual strategy of augmenting capacity between consecutive generations of DWDM networks by increasing the bit rate per channel will start to be challenged as theoretical capacity limits are approached. Therefore, capacity augmentation alternatives such as using more wavelength bands, exploiting multi-mode fibre transmission and deploying additional fibre pairs or multi-core fibres are being investigated. The adoption of one or more of these alternatives will impact the architecture of ROADM nodes. Particularly, a significant increase in the number of fibre pairs incoming/outgoing from a node can be expected when using multi-fibre links, demanding more complex and expensive switching devices and/or configurations. This work addresses the described forward-looking scenario, proposing and evaluating novel design strategies for the express layer of ROADM nodes such that scalability and cost-effectiveness are preserved while mitigating the potential increase of traffic blocking.

Pere Pérez-Millán
Supercontinuum based solutions focused on industrial customer needs
P. Pérez-Millán, J. Abreu-Afonso, S. Torres-Peiró, V. Otgon, and H. Muñoz-Marco
FYLA LASER SL, Paterna (Valencia), Spain

FYLA manufactures ns, ps and fs proprietary fiber lasers in the range of 1, 1.5, 2.0 µm wavelengths and supercontinuum VIS to NIR bands. The go-to-market approach of FYLA is based on an R+D strategy deeply focused on our (current and future) customer needs. This paper presents a selection of advanced solutions based in supercontinuum illumination that have been developed to satisfy such needs and the market sectors where they are framed.

Jiří Petráček
Nonreciprocal transmission in coupled nonlinear waveguides with loss and gain
J. Petráček, Brno University of Technology, Czech Republic
We investigate the effect of loss and gain on transmission characteristics of Kerr-nonlinear directional couplers. We consider a symmetric coupler made of two hybrid dielectric-plasmonic slot waveguides and introduce asymmetric gain profile. We classify the resulting steady states of the nonlinear system and demonstrate that asymmetric steady states, which can only occur for an asymmetric gain profile, cause strongly nonreciprocal transmission.

Erwan Pincemin
Cascaded all-optical sub-channel add/drop multiplexing from a 1-Tb/s MB-OFDM or N-WDM super-channel with ultra-low guard-bands
E. Pincemin1, M. Song1, B. Baeuerle2, A. Josten2, D. Hillerkuss2, J. Leuthold2, R. Rudnick3, D.M. Marom3, S. Ben-Ezra4, J.F. Ferran5, D. Klonidis6, and I. Tomkos6
1Orange Labs Networks, Lannion, France
2ETH Zurich, Switzerland
3Hebrew University, Jerusalem, Israel
4Finisar Ltd., Israel
5W-Onesys, Barcelona, Spain
6Athens Information Technology, Marousi, Greece

Elastic optical networking (EON) is one of the key enablers to increase fiber capacity by adapting the network resources to the dynamically varying traffic demands, thus avoiding the requirement for over-provisioning. This adaptability is determined by the features of the elastic super-channel (Sp-Ch) and switching technology capabilities. Network traffic routing can be performed transparently at the Sp-Ch level in a similar way to today’s WDM networks, but with spectrally adaptive channels and switching elements. Although EON addresses the capacity-on-demand issue, it depends on costly and power consuming electronic aggregation/grooming functions (i.e. OTN) at network nodes. Any processing of the Sp-Ch contents requires the reception of the whole Sp-Ch at the node and, subsequently, the electronic processing and switching/grooming of its sub-channel (Sb-Ch) contents. Recently, a new generation of elastic switching solutions based on high spectral resolution (HSR) optical filters and wavelength selective switches (WSSs) has emerged. These filtering and switching elements offer dynamic all-optical traffic aggregation/grooming (AOTG) at the Sb-Ch level. Such solutions can achieve ultra-fine switching granularity, resulting in reduced network cost compared to electronic-based alternatives. We show here cascaded 100-Gb/s sub-channel add/drop from a 1-Tb/s MB-OFDM or Nyquist-WDM super-channel having ultra-low inter-sub-channel guard-bands within a recirculating loop via a hierarchical ROADM using high-resolution filters, showcasing up to 1000-km transmission reach and five ROADM node passages for the add/drop sub-channel when hybrid Raman-EDFA is used.

Armando Nolasco Pinto
Quantum communications: An engineering approach
A.N. Pinto1,4, N.A. Silva1,4, N.J. Muga1,3,4, Á.J. Almeida4, and D.F. Pereira2,4
Dept. of Electronics, Telecom. and Informatics, University of Aveiro, Portugal
2Dept. of Physics, University of Aveiro, Portugal
3i3N Aveiro, Portugal
4Instituto de Telecomunicações, Aveiro, Portugal
In this paper, we review our recent advances in the implementation of quantum communication systems. We start by discussing two types of optical quantum sources. A source based on a fainted semiconductor laser and another based on the four-wave mixing process. Afterwards, we discuss information encoding techniques in quantum states suitable to be used in fibre-optic quantum communication systems. Next, we present a non-intrusive technique to control random polarization rotations in polarization-encoded quantum communication systems. Finally, we discuss a quantum oblivious transfer protocol implementation based on the noisy storage model and on the use of hash functions.

Henrique Salgado
Analysis of resonant tunnelling diode oscillators under optical modulation
J.S. Tavares1,2, L.M. Pessoa1, J.M.L. Figueiredo3, and H.M. Salgado1,2
1INESC TEC, Porto, Portugal
2Faculty of Engineering, University of Porto, Porto, Portugal
3Departamento de Física, CEOT, Universidade do Algarve, Portugal

In this paper, we investigate the optical modulation characteristics of a resonant tunnelling diode (RTD) oscillator. This preliminary work on the first RTD-PD oscillators with an optical window available from the iBROW project demonstrate that this device can effectively be used to accomplish amplitude and frequency modulation with light injection.

Sergey Sergeyev
Rogue waves and mode locking driven by vector resonance multimode instability
S.V. Sergeyev, H. Kbashi, and S.A. Kolpakov
Aston Institute of Photonic Technologies, Aston University, UK

Modulation instabilities discovered more than fifty and hundred fifty years ago created since then a framework for study complexity of different wave phenomena including turbulence and rogue waves. Using Erbium-doped fiber laser without any previously studied mode-locking mechanisms, here for the first time we demonstrate both experimentally and theoretically a new type of modulation instability, namely Vector Resonance Multimode Instability, leading to tunability of the laser dynamics from turbulence including rogue waves to the stable pulse train similar to the laser mode-locking regime.

Mariia Sorokina
Sparse identification for nonlinear optical communication systems
M. Sorokina, S. Sygletos, and S. Turitsyn
Aston Institute of Photonic Technologies, Aston University, Birmingham, UK

We have developed a low complexity machine learning based nonlinear impairment equalization scheme and demonstrated its successful performance in SDM transmission links achieving compensation of both inter- and intra- channel Kerr-based nonlinear effects. The method operates in one sample per symbol and in one computational step. It is adaptive, i.e. it does not require a knowledge of system parameters, and it is scalable to different power levels and modulation formats. The method can be straightforwardly expanded to multi-channel systems and to any other type of nonlinear impairment.

Michela Svaluto Moreolo
Towards advanced high capacity and highly scalable software defined optical transmission
M. Svaluto Moreolo, L. Nadal, and J.M. Fabrega
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Castelldefels (Barcelona), Spain
Software defined optical transmission (SDOT) and sliceable programmable transceivers, exploiting multiple dimensions and photonic technologies, enable to support future networks with advanced and novel functionalities, meeting the capacity and reach targets, according to the segment requirements. Programmability and modularity are crucial for scalability and functional disaggregation, facilitating a migration towards flexible and disaggregated networking paradigms, where the infrastructure can be suitably sized, growing as needed.  This work focus on SDOT enabling technologies, design guidelines and related trade-offs in terms of complexity and cost. Furthermore, SDOT programmability and modularity are discussed.

Ioannis Tomkos
On the benefits of FMF based data center interconnection utilizing MIMO-less PAM-M transceivers
B. Shariati1,2, N-P. Diamantopoulos1,3, D. Klonidis1, J. Comellas2, and I. Tomkos1
Athens Information Technology (AIT), Marousi, Greece
2Universitat Politécnica de Catalunya (UPC), Barcelona, Spain
3currently with NTT Device Technology Laboratories, NTT Corp., Atsugi, Kanagawa, Japan

Space division multiplexing (SDM) has been proposed to cost-effectively increase the capacity of optical transmission systems. The cost savings can be realized by introducing some levels of spatial integration of elements. However, spatial densification increases the crosstalk (XT) interactions among spatial channels. The XT is expected to be mitigated by MIMO processing, however, it increases the power consumption which in turn can make MIMO based SDM solutions impractical. This is a major issue for datacenters exploiting SDM solutions. Therefore, removing/lightening the burden imposed by MIMO processing can make SDM a more favorable solution. In this paper, we propose a datacenter interconnection network (DCIN), utilizing PAM-M transceivers, which can circumvent MIMO processing. It can be achieved by designing proper fibers (e.g. elliptical core FMF) in which the likelihood of mixing between mode-groups can be reduced. A key contribution of this work is the development of an analytical model to estimate the maximum reach that PAM-M (M = 4,8) signals can travel through coupled SDM fibers, targeting intra- and inter-DCs applications. We then demonstrate that FMF with MIMO-less PAM-M transceivers can significantly reduce the cabling complexity, and consequently, the cost of DCINs compared to single wavelength multi-mode or single-mode fibers based deployments.

Christine Tremblay
Dynamics of polarization fluctuations in aerial and buried links
C. Tremblay1, A. Michel1, Marie J. Tanoh1, M.P. Bélanger2, S. Clarke2, D.W. Charlton2, D.L. Peterson3, and G.A. Wellbrock3
1École de Technologie Supérieure, Montréal, Canada
2Ciena Corp. Nepean, Canada
3Verizon, Richardson, TX, USA

The coherent optical systems based on polarization multiplexing deployed in core networks in the last years have generated a renewed interest for the study of polarization effects in fiber optic links. Fluctuations of the state of polarization (SOP) of the optical signal, combined with polarization-dependent loss (PDL) and polarization mode dispersion (PMD), can affect the performance of coherent optical communication systems. The dynamics of the polarization fluctuations can be expected to be strongly dependent on the characteristics of the fiber plant. Some polarization measurement data have already been obtained using coherent transponders or a polarimeter, but on a few links only and mostly over short periods of time. Recently, the results of a 22-month SOP activity monitoring on an in-service aerial installation of 750 km have been reported, which provides more insight into the polarization activity in optical ground wire (OPGW) fiber cables.  In this paper, we report on a long-term SOP activity monitoring on an experimental metro ring network using a polarimeter and a dual polarized, modulated with dual-polarization quadrature phase-shift keying (DP-QPSK) modem à 100 Gb/s. The temporal and frequency dynamics of the polarization fluctuations and SOP transients observed in the buried fiber plant are presented and compared to those reported in the aerial installation.

Stefan Wabnitz
Spatio-temporal beam dynamics in multimode nonlinear optical fibers
K. Krupa1-3, D. Modotto1, V. Couderc2, A. Barthelemy2, A. Tonello2, G. Millot3, and S. Wabnitz1,4
1Dipartimento di Ingegneria dell’Informazione, Università di Brescia, Italy
2Université de Limoges, XLIM, UMR CNRS 7252, France
3Université Bourgogne Franche-Comté, ICB UMR CNRS 6303, Dijon, France
4Novosibirsk State University, Russia

We overview recent advances in the spatio-temporal nonlinear dynamics of optical pulses propagating in multimode optical fibers. The Kerr effect leads to spatial beam self-cleaning in a graded index multimode optical fiber, followed by sideband series generation spanning multiple octaves, and spectrally flat, effectively single mode supercontinuum spanning from the visible to the mid-infrared. Enhancement of Kerr beam self-cleaning has been observed in active fiber with step index profile. Moreover, mutual self-cleaning has recently been reported for both the fundamental and the second harmonic beam in optically poled multimode fibers with both cubic and quadratic nonlinearity.

Krzysztof Walkowiak
Spectrum usage for various SDM scenarios
P. Lechowicz1, K. Walkowiak1, and M. Klinkowski2
1Wroclaw University of Science and Technology, Poland
2National Institute of Telecommunications, Poland

Space division multiplexing (SDM) seems to be a promising solution with the scaling potential to overcome the possible capacity crunch problem in optical backbone networks. The main goal of this paper is to provide a detailed analysis of three SDM scenarios, namely, SDM-Fixed, SDM-Single, and SDM-Flexible in terms of the spectrum usage and the wastage of spectral resources due to guardbands and resource overprovisioning.

Xu Wang
Anti-aliasing technique for time-stretch imaging system
Xu Wang1 and Bo Dai2
1The Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, UK
2Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, China

Time-stretch imaging is a novel ultrafast imaging technique, which is based on space-to-time-to-wavelength mapping. We proposed an anti-aliasing technique based on optical time-division multiplexing. With the antialiasing technique, we can acquire a large amount of image information by using relatively low-sampling-rate electronic digitizer. Numerical analysis shows that the image quality can be improved by 4.16 dB comparing to that without using the anti-aliasing technique and at least 2.3 dB comparing to those digital signal processing techniques such as bilinear, bicubic and nearest-neighbor interpolation and Lanczos resampling techniques. In addition, we experimentally demonstrated a line-scan imaging system, which has the scan rate of 38.88 MHz. Defects and scratches on the object that were not identifiable originally can be clearly distinguished after using the proposed anti-aliasing technique.

Mike Wolf
PAM-transmission with optimal detection for dispersive optical channels with intensity modulation and direct detection
M. Wolf, S.A. Cheema, and M. Haardt
Communications Research Laboratory, Ilmenau University of Technology, Germany
Digital transmission over dispersive optical channels suffers fromintersymbol interference (ISI).We study themutual information of PAM transmission under the intensity modulation and direct detection (IM/DD) constraint, where we model the optical channel as a Gaussian low-pass filter, which is a valid attempt for polymer optical fibers (POF) and allows closed form expressions. In particular, we study the properties of the sample whitened matched filter, which enables the derivation of the mutual information for PAM with IM/DD. The information rate (lower bound) of PAM with equally probable input symbols is compared to an information rate approximation of DC biased multiple sub-carrier modulation (MSM), where we approximate the effect due to threshold clipping as Gaussian distributed noise, and to the information rate of asymmetrically clipped MSM. The required optical power for uncoded block transmission at a bit error rate of 10-3 is also presented. In the case of PAM, a unique word approach is used, and decision-feedback equalization is performed directly at the output of a sample whitened matched filter realized in thefrequency domain. The results show that PAM with a rectangular pulse shape outperforms the  other schemes.

Elaine Wong
Latency-aware optimisation framework for cloudlet placement
E. Wong, S. Mondal, and G. Das
University of Melbourne, Australia

Promising far-reaching benefits that will pervade healthcare, industrial automation, autonomous driving, smart grid, and edutainment, the Tactile Internet is envisaged to improve our everyday life. Described as a communications infrastructure that facilitates real-time human-machine interaction through visual, audio, and tactile feedback, anytime and anywhere, its realization hinges upon achieving ultra-low latency required for real-time haptic communication. To meet stringent latency requirements, the deployment of cloudlets (distributed cloud computing and storage at the very edge of the network) has been proposed. In this talk, we will motivate the drive for cloudlets in a Tactile Internet infrastructure and briefly discuss our on-going research in cloudlet placement and network planning.

Marc Wuilpart
Distributed measurement of supercontinuum generation in conventional and highly nonlinear optical fibers
M. Wuilpart1, R. Hontinfindé1, S. Coulibaly2, P. Mégret1, and M. Taki2
1Electromagnetism and Telecommunications Department, Faculté Polytechnique, Université de Mons, Belgium
2Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, France

Supercontinuum generation results from the spectral broadening of an intense light arising from the interplay between several nonlinear optical effects. In this talk, a non-destructive optical time domain reflectometry set-up is proposed to measure the spatial evolution of the spectral broadening induced along an optical fiber. The method is based on the measurement of the Rayleigh backscattered signals generated by the various components of the spectral broadening. The system was experimentally tested on conventional and highly nonlinear fibers. The experimental data obtained with the proposed method were in good agreement with the optical spectra measured by an optical spectrum analyzer at the fiber outputs. The proposed measurement method can be applied without damaging and/or perturbing the intrinsic dynamics of the supercontinuum generation.

Changyuan Yu
Single measurement Brillouin optical time domain analyzer based on digital optical frequency comb
Chao Jin1, Zhaohui Li2, Chao Lu1, and Changyuan Yu1
1Photonics Research Centre, The Hong Kong Polytechnic University, Hong Kong
2State Key Laboratory of Optoelectronic Material and Technologies and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China

An ultra-fast distributed Brillouin optical time domain analyzer (BOTDA) is proposed and experimentally demonstrated based on coherent detection of digital optical frequency comb (DOFC) probe signal. The phase shift of each frequency tone induced by Brillouin interaction, corresponding to the Brillouin Phase Spectrum (BPS), is simultaneously measured in a single data acquisition without averaging process. Based on coherent detection of BPS, single-measurement BOTDA sensor is demonstrated with a measurement time of 100 μs, with a spatial resolution of 51.2 m along 10 km fibre. Vibration frequency up to 1 kHz of dynamic measurement has been successfully observed.

5GT invited presentations: 

Liam Barry
Converged wired and wireless services in next generation optical access networks
C. Browning1, A. Farhang1, A. Saljoghei2, N. Marchetti2, V. Vujicic1, L.E. Doyle2, and L.P. Barry1
1Department of Electronic Engineering, Dublin City University, Ireland
2CONNECT Research Centre, Dunlop Oriel House, Trinity College Dublin, Ireland
5G communications will require the effective transmission of new radio signals through fiber networks, in order to facilitate the proliferation of antenna sites as well as greater pooling of resources. Next generation optical access networks can provide an efficient platform for mobile x-haul. Techniques discussed in this paper shows how both wired and 5G wireless services may be converged over a single fiber infrastructure, and how optical networking can be harnessed in order to provide flexible millimeter-wave radio-over-fiber.

Anne-Laure Billabert
Simulation approach of wireless OFDM and FBMC signals transmission over fiber based on equivalent electrical models
A-Laure. Billabert1, A. Kabalan1, S. Faci1, R. Zakaria2, M. Moutaly1, and C. Algani1
ESYCOM, Le Cnam, Paris, France
2Cédric, Le Cnam, Paris, France

In this paper, we present the impact of a Radio over fiber (RoF) link on the transmission of a signal dedicated to wireless link. Comparison is given between OFDM and FBMC based wireless signal by simulation with the electrical modelling approach of O/E and E/O devices and optical components. The considered link concerns the Intensity Modulation - Direct Detection (IM-DD) architecture where the wireless signal is transmitted at the intermediate frequency. The simulation system includes the noise sources and nonlinearity of each component making thus the easy study of the impact of each one separately. It is then possible to quantify the degradation of the transmitted signal in term of error vector magnitude (EVM) or bit error rate (BER). Thus, the system architecture can be optimized for various applications and furthermore depending on the number of users.

Nathan Gomes
Ethernet-based fronthauling for cloud- and virtualized-radio access networks
P. Assimakopoulos, G.S. Birring, M.K. Al-Hares, and N.J. Gomes
Communications Research Group, University of Kent, Canterbury, UK
Standardization bodies such as IEEE and 3GPP, as well as other interest groups, are in the process of defining and standardizing different functional subdivisions within mobile network base stations, primarily to reduce the data rate requirements imposed on the transport architecture by 4thand 5th generation mobile systems. Ethernet is considered the leading candidate for the transport architecture as it brings benefits from structural and operational convergence in what is now termed the “xhaul” (x signifying front, mid or back). This paper reports on the performance of different functional subdivisions over a bridged Ethernet network and presents some of the main issues that occur when internetworking at the Ethernet transport level. In particular, it examines Priority-based Scheduling within an Ethernet fronthaul, which is also a subject of active standardization by IEEE.

Young Lee
Scalable telemetry and network autonomics in ACTN SDN controller hierarchy
Young Lee1, R. Vilalta2, R. Casellas2, R. Martínez2, and R. Muñoz2
1Huawei Research Center, USA
2Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Castelldefels, Spain

Abstraction and Control of TE Networks (ACTN) refers to the set of virtual network operations needed to operate, control and manage large-scale multi-domain, multi-layer and multi-vendor TE networks, so as to facilitate network programmability, automation, efficient resource sharing. This paper provides scalable telemetry streaming mechanisms that describe Key Performance Indicator (KPI) telemetry and network autonomics in the context of ACTN SDN controller.

Raul Muñoz
Integrating optical transport network testbeds and cloud platforms to enable end-to-end 5G and IoT services
R. Muñoz, R. Vilalta, R. Casellas, A. Mayoral, and R. Martínez
Centre Tecnològic de Telecomunicacions de Catalunya, Communication Networks Division, Optical Networks and Systems Department, Castelldefels, Spain
This paper presents the integration solution carried out in the CTTC ADRENALINE testbed to provide an end-to-end converged multi-technology SDN/NFV transport network involving all network segments (access, metro and core) and distributed cloud resources (edge, core). The proposed solution aims at enabling the development and test of 5G and IoT services supporting a wide variety of use cases from different vertical industries, such as automotive, e-health, energy, media or smart cities. To this end, the ADRENALINE testbed is adopting the following technologies to meet the stringent requirements of 5G and IoT; i) high-capacity, flexible and cost/energy-efficient software-defined optical transmission technologies for access, metro and core networks; ii) highly-scalable Ethernet technologies for aggregation and switching of flows with quality of service (QoS); iii) Core and edge cloud for the deployment of virtualized network functions (VNFs)and virtual application functions (VAFs) in edge nodes, central offices or core data centers for both mobile and fixed users (e.g., LTE/EPC, video analytics, mission-critical IoT applications, augmented reality, data caching); iv) SDN/NFV control and orchestration system to provide global orchestration of the network and cloud infrastructure resources (optical, Ethernet, computing, storage), service function chaining of VNFs and VAFs, as well as network slicing for multi-tenancy.

ACCESS invited presentations: 

Pierpaolo Boffi
FDM exploitation for next access and data networks
A. Gatto, P. Parolari, and P. Boffi
Politecnico di Milano, Dept. Electronics, Information and Bioengineering - PoliCom Lab, Italy

By means of the dynamic and flexible choice of subcarrier modulation and spacing, frequency division multiplexing is demonstrated to overcome the system bandwidth limits achieving high capacity, both for datacenter interconnections and for multiple access passive optical networks.

Ivan Cano
Bidirectional real-time DSP-less heterodyne UDWDM-PON
I.N. Cano, J.C. Velásquez, V. Polo, and J. Prat
Universitat Politécnica de Catalunya, Barcelona, Spain

We demonstrate a bidirectional real-time symmetric 1.25Gbit/s per user UDWDM-PON with simple DSP-less transceivers. ODN losses of 38 dB are achieved in a 12.5 GHz grid with HD video transmission.

Yun Chung
Ultrahigh-speed short-reach fiber-optic link based on directly modulated lasers
Minsik Kim, Hoon Kim, and Yun C. Chung
Korea Advanced Institute of Science and Technology, Daejeon, Korea

Ultrahigh-speed (>50 Gb/s) short-reach fiber-optic links can be implemented cost-effectively by using directly modulated lasers (DMLs).  For demonstrations, we successfully transmit 56-Gb/s PAM-4 signal over 20 km of SSMF by using 1.5-mm DML and 117-Gb/s DMT signal over 30 km of SSMF by using 1.3-mm DML.

Milorad Cvijetic
Multidimensional optical access networks with spectral-spatial interworking
M. Cvijetic1, I. Tomkos1,2, and Wenbo Gao1
1University of Arizona, USA
2Athens Institute of Technology, Greece

Multidimensional approach based on employment of both spatial and spectral modes in an optical access network can enable not only increase in the network throughput, but also enhance its dynamic and elastic character through spectral-spatial interworking and employment of an advanced software defined (SDN) networking model.  In this paper we introduce the concept of virtual bandwidth exchange among end-users in multidimensional optical access networks and methodology for the throughput maximization in networks with plurality of heterogeneous end-points.

Josep Fabrega
Mobile front-/back-haul delivery in elastic metro/access networks with sliceable transceivers based on OFDM transmission and direct detection
J.M. Fabrega1, M. Svaluto Moreolo1, L. Nadal1, F.J. Vílchez1, J.P. Fernández-Palacios1, and L.M. Contreras2
1Centre Tecnologic de Telecomunicacions de Catalunya (CTTC), Castelldefels, Spain
2Telefónica I+D, Madrid, Spain

A transparent and dynamic delivery of mobile front-/back-haul for converged metro/access elastic networking is experimentally demonstrated employing sliceable bandwidth/bitrate variable transceivers based on orthogonal frequency division multiplexing and direct detection. Testbed experiments show successful transmission after 60 km and up to 100 Gb/s data rate.

Ali Hammadi
PON data centre design with AWGR and server based routing
R. Alani, A. Hammadi, T.E.H. El-Gorashi, and J.M.H. Elmirghani
School of Electronic and Electrical Engineering, University of Leeds, UK

Passive Optical Networks (PONs) with their proven performance in access networks can provide solutions to the challenges facing modern data centres. In this paper, we study a PON architecture where Arrayed Waveguide Grating Routers (AWGRs) and servers are used to route traffic. We optimize the wavelength routing and assignment in the design and show through a benchmark study that the PON data centre architecture reduces the power consumption by 83% compared to the Fat-Tree architecture and 93% compared to the BCube architecture.

Alberto Lometti
Extending the scope of OTN to access and metro networks
A. Lometti, S. Frigerio, and L. Ronchetti
SM Optics, Vimercate, Italy

Network based on OTN standard (ITU-T G.709), originally devised for core networks, are foreseen to play an important role also in metro and possibly access optical networks, because of the always increasing bandwidth needs as well as of some new (at least numerically) requirements like latency and jitter control. In a historical timeframe in which the standardization activity is primarily focused on the extension of the hierarchy beyond 100Gb/s, in this paper we quickly recap the basics of OTN, some more recent standard trends, and describe a couple of access and metro applications to which the technology can be easily adapted, both for evolving legacy services, which still exist, to new transmission platforms and for delivering new 5G oriented services.

Carmen Mas Machuca
Providing broadband access to extremely sparsely areas
C. Mas Machuca and E. Grigoreva
Technische Universität München, Germany

The telecom arena has become very competitive in dense urban areas where the number of potential customers as well as the requirement of high bandwidth are very important. On the contrary, sparse areas are left outside the broadband roll out due to the scarce expected revenues and high predicted investments. This work aims at comparing different architectures combining different technologies from different aspects such as investments, power consumption and delivered bandwidth. A particular case study of a sparse area in Finland is analyzed in detail.

Josep Segarra
Flexible coherent UDWDM-PON adapting dynamically to different bandwidths
J. Segarra1, V. Sales1, J. Prat1, and L. Kazovsky2
1Universitat Politècnica de Catalunya, UPC, Barcelona, Spain
2Photonics and Networking Research Laboratory (PNRL), Stanford University, USA

Ultra Dense Wavelength Division Multiplexing (UDWDM) is a candidate for future Passive Optical Networks (PONs) to sustain the increase of access traffic, providing enhanced capacity with point-to-point logical connections while introducing the Wavelength-To-The-User (WTTU) concept. This is enabled by low cost coherent transceivers with high sensitivity, also furnishing increased splitting ratio and long reach extension. On the other hand, bandwidth demands are highly dynamic, driven by high definition video, cloud-computing traffic, next generation mobile networks and emerging Internet of Things (IoT). To support this dynamic pattern, reconfigurable capabilities are to be delivered to access and metro networks. In this paper we propose a flexible design of an UDWDM-PON, which adapts the available bandwidth to different classes of services and users, envisioning elastic flexible WDM grids for spectral efficiency and optimized metro network convergence.

BigNeO invited presentations: 

Adrian Asensio
Dynamic virtual network connectivity for C-RAN backhauling
A. Asensio, M. Ruiz, and L. Velasco
Universitat Politècnica de Catalunya (UPC), Barcelona, Spain

Aiming at satisfying in a cost-effective manner the forecast traffic growth that future mobile networks will need to support, traditional distributed Radio Access Networks (RANs) are evolving towards centralized architectures. Specifically, the Cloud-RAN (C-RAN) architecture has shown that can alleviate to some extent the ever increasing Total Cost of Ownership in mobile networks. The current trend in C-RAN is to separate Remote Radio Heads (RRH) with radio frequency (RF) functions and Baseband Units (BBU) gathering baseband processing. This functional split allows keeping RF modules close to the antennas while placing BBUs at centralized locations so they can be shared among different sites and even be virtualized. However, some issues still need to be addressed in future mobile networks, especially due to the dynamicity of services and the strict constraints imposed by the interfaces needed. Since connectivity reconfiguration for backhaul interfaces (X2 and S1) needs to be provided as an all-or-nothing request to enable mobile resources reconfiguration in a geographical area, in this paper we propose dynamic Customer Virtual Network (CVN) reconfiguration to be supported in metro and core network segments. Additionally, Such CVN requests must include Quality of Service constraints to ensure specific delay constraints, as well as bitrate guarantees to avoid service interruption. An efficient algorithm is presented for the CVN reconfiguration problem and exhaustive simulation results study its performance on realistic scenarios.

Ramon Casellas
Control plane architectures enabling transport network adaptive and autonomic operation
R. Casellas, R. Vilalta, A. Mayoral, R. Martínez, R. Muñoz, and L.M. Contreras
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Castelldefels, Spain

The maturity and flexibility of Software Defined Networking principles, favouring centralized control deployments, featured application programming interfaces and the development of a related application ecosystem, has paved the way for the design and implementation of advanced and adapted control plane architectures that specially target and enable efficient and massive monitoring and data collection.  In this line, the steady increase in the use of open and standard interfaces and data modelling languages, as well as a wide adoption (in a vendor independent way) of model-driven solutions and a unified approach for data collection and processing facilitates shifting the focus to the actual processing of information, towards autonomic networks and self- capabilities. Scoped to the control of an optical flexi-grid transport network, and in line with major industry trends, in this paper we cover our requirements for efficient data collection and processing, and we propose and detail a control and management architecture, building on the concepts of front-end and backend entities, dynamic instantiation of control plane functions within the ETSI NFV framework and the applicability to use cases such as in-operation network planning, on-demand network optimization and parameter tuning.

Paola Festa
Adapting the virtual network topology to near future traffic

F. Morales1, P. Festa2, M. Ruiz1, and L. Velasco1
1Optical Communications Group (GCO), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
2Dipartimento di Matematica e Applicazioni "R. Caccioppoli", Università degli Studi di Napoli Federico II (UNINA), Napoli, Italy

The introduction of new services requiring large and dynamic bitrate connectivity can cause changes in the direction of the traffic in metro and even core network segments along the day. This leads to large overprovisioning in statically managed virtual network topologies (VNT), designed to cope with the traffic forecast. To reduce expenses while ensuring the required grade of service, in this paper we propose the VNT reconfiguration approach based on current and near-future traffic matrices (VENTURE) to regularly adapt the topology to both, the current and future traffic volume and direction. The problem is formally stated, mathematically modeled and a heuristic algorithm is proposed to solve it.

Paola Festa
On the fast solution of the p-center problem
D. Ferone1, P. Festa1, A. Napoletano1, and M.G.C. Resende2
1Department of Mathematics and Applications “R. Caccioppoli”, University of Napoli FEDERICO II, Italy
2Mathematical Optimization and Planning, Amazon.com, USA

The p-center problem is one of the classical facility location problems which finds several applications in the field of the network planning and network optimization. Due to the increasing of bandwidth requirements, telecommunication operators are renewing the access networks in favoring of optical networks. Generally, the design of access network consists in determining the location of physical networks from a given list of potential locations. Indeed, in order to ensure the efficient usage of a limited number of resources, the identification of facility locations plays a central role. In this paper, we formally define the p-center problem, briefly survey the most efficient state of the art algorithms to approach it, and describe a new smart and fast local search able to find optimal or near-optimal solutions. We also discuss and analyze the results of our extensive computational experience on benchmark instances.

Lluís Gifre
Experimental assessment of big data-backed video distribution in the telecom cloud
L. Gifre1, M. Ruiz2, and L. Velasco2
1Universidad Autónoma de Madrid (UAM), Madrid, Spain
2Universitat Politècnica de Catalunya (UPC), Barcelona, Spain

The telecom infrastructure is undergoing a huge transformation since operators are deploying their own cloud infrastructure to provide cloud services and enabling Network Functions Virtualization (NFV). The resulting infrastructure is referred to as the telecom cloud. NFV decouples network functions from proprietary hardware appliances, so they can be implemented in software and deployed on virtual machines (VM) running on commercial off-the-shelf computing hardware.  One of the network functions currently being considered by many operators is Content Delivery Network (CDN) for live-TV and Video on Demand (VoD) distribution. In fact, a significant advance in video delivery is the standardized MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH) technique that enables media content delivering over the Internet using standard HTTP web server infrastructure. Besides, the CDN reconfiguration, motivated by an increase in the number of users demanding content, entails a Virtual Network Topology (VNT) reconfiguration to cope with the demanded connection capacities.  A Big Data-based CDN manager, fulfilling the ETSI NFV guidelines, is proposed to adapt the virtualized CDN function to current and future demand. Its feasibility to control virtualized components while collecting monitoring data is experimentally assessed in a real environment.

Miguel Gonzalez-Herráez
Protecting fiber-optic links from third party intrusion using distributed acoustic sensors
M.R. Fernández-Ruiz1, A. Garcia-Ruiz1, H.F. Martins2, J. Pastor-Graells1, S. Martin-Lopez1, and M. Gonzalez-Herraez1
1Departamento de Electrónica, Universidad de Alcalá, Escuela Politécnica Superior, Madrid, Spain
2FOCUS S. L., Madrid, Spain

A major cause of faults in optical communication links is related to unintentional third party intrusions (normally related to civil/agricultural works) causing fiber breaks or cable damage. Distributed acoustic sensors can be used to detect these threats to the fiber-optic infrastructure before they cause damage to the infrastructure and proactively re-route the traffic towards links were no threat is detected. In this talk we will review our recent progress on distributed acoustic sensing and will provide some key considerations for the deployment of these systems in connection with their use in the protection of optical networks.

Lei Guo
Green virtual network embedding mechanism based on scalable small cells in fiber-wireless access network for 5G
Pengchao Han, Lei Guo, Yejun Liu
School of Computer Science and Engineering, Northeastern University, Shenyang, China

The converged fiber-wireless network that can provide service to users with a high capacity, flexibility and reliability has become a promising “last mile” solution for the Fifth Generation (5G). Network virtualization is capable of shielding the heterogeneous features of physical networks and facing the emergence of Over the top (OTT) content, which is consistent with the vision of 5G, where energy efficiency is one of the key issues. This paper concerns the green virtual network embedding scheme in virtualized fiber-wireless access network for 5G, where the scalable small cell is designed. On one hand, the energy can be saved by decreasing the transmitting power of Remote Radio Heads (RRH) reasonably. On the other hand, the virtual node embedding can be optimized through zooming the coverage of small cells and the zero-loaded RRHs can be switched into sleep state for energy-saving.

Mirosław Klinkowski
Influence of modulation format transmission reach on performance of elastic optical networks
M. Klinkowski1, K. Walkowiak2, and P. Lechowicz2
1National Institute of Telecommunications, Wroclaw, Poland
2Wroclaw University of Science and Technology, Poland

The flexible-grid elastic optical network (EON) technology is a new optical networking approach that can substitute in a near future the fixed-grid wavelength division multiplexing (WDM) technology. EONs make use of advanced modulation formats (MFs), spectrum-selective switching technologies, and flexible frequency grids, which increase spectral efficiency and improve bandwidth scalability of the network. The previous papers that were focused on optimization of EONs take many different assumptions regarding the transmission reach of MFs. But, according to the best of our knowledge, there have been no comparative analysis showing how transmission reach models impact the network performance in terms of both spectrum and transceiver usage. In this paper, we address joint optimization of these two key resources in EONs. In our study, we consider that transceivers are used for both transmission and signal regeneration purposes. The main contribution of the paper is a detailed analysis of the MF transmission reach impact on the spectrum consumption and transceiver usage in EONs. We present and discuss results of extensive numerical experiments run on representative network topologies with realistic physical assumptions considering various transmission reaches of the applied MFs.

Fernando Morales
Data analytics based origin-destination core traffic modelling
F. Morales, M. Ruiz, and L. Velasco
Optical Communications Group (GCO), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
Traffic monitoring is an essential task for network operators since it allows evaluating network performance. Monitoring data from origin-destination (OD) traffic in core virtual network topologies can be collected from packet nodes and stored in a repository for further analysis, e.g., to detect anomalies or to create predicted traffic matrices for the near future. In this paper we propose a set of modules to support data analytics-based algorithms along with a machine learning procedure based on artificial neural networks (ANN) that provides robust and adaptive traffic models.

Marc Ruiz
Combining a machine learning and optimization for early pre-FEC BER degradation to meet committed QoS
A.P. Vela1, M. Ruiz1, F. Cugini2, and L. Velasco1
1Optical Communications Group (GCO), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
2CNIT, Pisa, Italy

Monitoring the physical layer is key to detect bit error rate (BER) degradation caused by failures and to identify the cause of the failure and localize the failed elements. Once the failure has been detected, actions can be taken to reduce as much as possible its impact on the network. Commercially available optical equipment are able to correct degraded optical signals by means of Forward Error Correction (FEC) algorithms. A value of pre-FEC BER over a pre-defined threshold would imply a non-error-free post-FEC transmission and, as a result, communication would be disrupted. Therefore, a prompt detection of lightpaths with excessive pre-FEC BER can help to greatly reduce such SLA violations, in particular when supporting vlinks. As a result of the above, it would be desirable to anticipate such degradations and apply re-optimization to re-route those affected demands according to their SLAs in order to reduce the affected traffic after the degradation is detected. Designing algorithms capable of promptly detect distinct BER anomaly patterns would be desirable. The objective would be to anticipate intolerable BER values as much as possible aiming at leaving enough time to plan a re-routing procedure during off-peak hours. In this paper, we propose an effective machine learning-based algorithm to localize and identify the most probable cause of failure impacting a given service, as well as a re-optimization algorithm to re-route affected demands, targeting at reducing SLA violation. Results show that the proposed detection and re-routing algorithms noticeably reduce bandwidth and number of demands affected.

Pontus Sköldström
Making powerful friends: Introducing ONOS and Net2Plan to each other
P. Sköldström1, Ć. Rožić2, and J-J. Pedreno-Manresa3
1RISE Acreo AB, Kista, Sweden
2Athens Information Technology, Marousi, Greece
3Universidad Politécnica de Cartagena, Spain

In this paper, we present our efforts for integrating network control and network planning, connecting the popular open-source ONOS control platform with Net2Plan, an open source network planner. The integration allows ONOS to use Net2Plan, combined with our resource allocation framework, as an on-line network optimization tool, calculating and re-routing paths as new requests arrive. It also lets Net2Plan obtain an up-to-date topology from ONOS. Net2Plan can then use the topology and our algorithms to perform planning operations such as investigating hypothetical questions about consequences of network failures or additional network equipment. The interface also lets the paths computed by the algorithms running on Net2Plan to be transferred to ONOS and implemented in the running network. While we currently only support IP/Optical networks, additional layers could easily be incorporated. As an interesting side-effect, code used for network simulation can be instrumented and applied to the real network.

Alba Vela
Bringing data analytics to the network nodes for efficient traffic anomalies detection
A.P. Vela, M. Ruiz, and L. Velasco
Universitat Politècnica de Catalunya (UPC), Barcelona, Spain

Traffic anomalies can create network congestion, so its prompt and accurate detection would allow network operators to make decisions to guarantee the network performance avoiding services to experience any perturbation. In this paper, we focus on origin–destination (OD) traffic anomalies; to efficiently detect those, we study two different anomaly detection methods based on data analytics and combine them with three monitoring strategies. In view of the short monitoring period needed to reduce anomaly detection, which entails large amount of monitoring data to be collected and analyzed in a centralized repository, we propose bringing data analytics to the network nodes to efficiently detect traffic anomalies, while keeping traffic estimation centralized. Exhaustive simulation results on a realistic network scenario show that the monitoring period should be as low as possible (e.g., 1 min) to keep anomaly detection times low, which clearly motivates to place traffic anomaly detection function in the network nodes.

Darko Zibar
Machine learning techniques for optical communication system optimization
D. Zibar, J. Wass, J. Thrane, and M. Piels
DTU Fotonik, Lyngby, Denmark

In this paper, machine learning techniques relevant to optical communication are presented and discussed. The focus is on applying machine learning tools to optical performance monitoring and performance prediction.

CTS invited presentations: 

Noureddine Boudriga
The design of an optical wireless sensor network based train vibration monitoring system
W. Abdallah and N. Boudriga
Communication Networks and Security Research Lab., University of Carthage, Tunisia

Vibration monitoring and analysis technology is of significant importance in scientific measurements and engineering applications such as transportation, since vibration may affect the health of moving vehicles. In particular, high speed trains may be subject to damages when their structures experience extremely high vibrations. For this, highly moving vehicles (such as trains and planes) need to be equipped with systems that are able to measure vibration, monitor the health structure, and react on the occurrence of unacceptable events. In this paper, we investigate the design of an optical wireless sensor network using laser beam reflection and VLC technology deployed on railway tracks to monitor and analyze the vibration patterns caused by the train motion and the quality of the rails it is using. Our architecture is based on measuring efficiently the train structure intrinsic vibration as well as the vibration due to the interaction between the train and railway tracks. To this purpose, we propose two types of light based sensor node architectures capable of sending and receiving light signals at controllable frequencies to cope with the intensity of the vibration, analysing the local structure health, and helping decision making to react to vibration related events occurring in a distributive manner on the train. The measurements and communication features of our sensor network include a tight estimation of the amplitude and the frequency of the train vibration during motion, geographic localization of the measurements, and real time communication between the sensors nodes and the embedded controlling centre. Finally, a numerical experimentation is conducted to evaluate the efficiency of the proposed optical wireless sensor network.

Joan García-Haro
A self-adaptive approach for traffic lights control in an urban network
M-D. Cano1, R. Sanchez-Iborra2, B. Freire-Viteri1, A-J. Garcia-Sanchez1, F. Garcia-Sanchez1, and J. Garcia-Haro1
1Department of Information and Communication Technologies, Universidad Politécnica de Cartagena, Spain
2Department of Information and Communications Engineering, University of Murcia, Spain

The use of adaptive traffic lights controllers represents an affordable approach to improve vehicular traffic conditions. In isolated intersections or local areas with a limited number of traffic lights, numerous works from the related open literature have achieved excellent results in key performance metrics. Nevertheless, an urban network environment poses important challenges for adaptive control, mainly due to the stochastic and non-linear nature of the events and the increasing number of interdependencies among them. In this paper, we introduce a self-adaptive method able to control traffic lights in an urban network. Our policy relies on both current traffic data and a “window” of historical data, from which each intersection controller proactively decides the measures to be taken. Simulations have been conducted to evaluate the performance of our proposal obtaining interesting findings to discuss.

Kira Kastell
A comparison and analysis of simulation scenarios for VANETs with focus on multilane motorways
K. Kastell, Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
VANETs are playing an increasing role in the development of communication and traffic assistance in transportation. Therefore mobility simulations are needed to predict the impact of new ideas on the VANET. But the interest in adding new applications to vehicles may differ largely according to the traffic scenarios. It seems too complicated to have one integrated mobility simulator that deals with inner city as well as with rural or motorway scenarios. Also the choice of an appropriate propagation model plays a role. In this paper the different scenarios are described. The multilane motorway scenario is described more detailed with respect to different analysis interests.

Tetsuya Kawanishi
Concept of sensor over fibres and its application to high resolution millimeter-wave radar
T. Kawanishi1,2, A. Kanno2, and N. Yamamoto2
1Waseda University, Tokyo, Japan
2National Institute of Information and Communications Technology (NICT), Tokyo, Japan

This paper describes the concept of sensor over fibres (SoF), consisting of many sensor heads connected by fibre networks. SoF transfer waveforms from the sensor heads and performs joint signal processing to achieve high-resolution and agile imaging, while wireless sensor networks (WSN) are digital networks to collect measured data at small sensors. SoF can compile information from sensor heads coherently at central signal processing units. We will also share applications of SoF technologies, such as high resolution millimetre-wave radar for airport runway surveillance.

Angeles Losada
Temperature sensitivity of POF links for avionics applications
A. López1, Xing Jiang2, M.A. Losada1, J. Mateo1, D. Richards2, N. Madamopoulos3, and N. Antoniades2
1GTF, Aragón Institute of Engineering Research (i3A), Universidad de Zaragoza, Spain
2College of Staten Island, The City University of New York, USA
3City College of NY, The City University of New York, USA

We present an experimental study of the temperature sensitivity of three different step-index 1‑mm PMMA fibers. Two of these fibers have a special jacket to sustain high temperatures: BH‑4001 and LHXE‑4001 and the other is a standard, GH‑4001 fiber with a polyethylene jacket. We show that the fibers perform well within the manufacturer specified temperature operating ranges. Predictably, higher than specified temperatures can result in permanent damage and permanent performance degradation. This work expands our previous work on modelling POF on various fiber types and lengths, focusing on the short links found on airplanes.

Mike Parker
Ultra-low latency 5G CHARISMA architecture for secure intelligent transportation verticals
M.C. Parker, K. Habel, G. Koczian, S.D. Walker, V. Jungnickel, C. Canales-Valenzuela, M.S. Siddiqui, Y. Liu, J.C. Point, A. Foglar, M. Ulbricht, E. Zetserov, and D. Levi
Metro, Access and In-House Systems Group, Photonic Networks and Systems, Fraunhofer Heinrich Hertz Institute, Berlin, Germany

We describe low end-to-end latencies of 6.69 ms in the 5G CHARISMA network, that has been optimised for both device and system technologies speed, as well as with its virtualised, hierarchical and distributed, edge-centric architecture, that processes data as near as possible to their source and destination. Such an ultra-high speed 5G network can be utilised in intelligent transport system (ITS) applications, and we describe a public transport bus-based use case that takes advantage of the CHARISMA capabilities.

Vladimir Rastorguev
Estimation of potential characteristics of onboard radar for ice surface monitoring
A.E. Ananenkov, A.I. Kanaschenkov, V.M. Nuzhdin, V.V. Rastorguev, and А.М. Smolyar
Moscow Aviation Institute (National Research University), MAI, Moscow, Russia

In this paper the potential characteristics of an airborne radar (AR) of an unmanned aerial vehicle (UAV) that monitors the ice situation along the Arctic traffic route are looked. Such radars provide operational, round-the-clock and all-weather monitoring of ice conditions for searching for divorces and threatening icebergs, and as a result, it increases the safety of navigating ships and oil platforms exploitation in the northern regions of the world's oceans. The possibilities of operation of the radar in the mode of measuring the height of the ice surface relief are analyzed. The potential characteristics of the radar with the interferometric method of measuring the relief height are estimated.

Vladimir Rastorguev
Researching of road objects radar signatures in the collision prevention automobile radar
Bui Sy Hanh, V.V. Rastorguev, and P.V. Sokolov
Moscow Aviation Institute (National Research University), MAI, Moscow, Russia
The report observes the results of radar signatures investigating and the road objects radar images (RI) statistical characteristics analysis in relation to automobile radar system (ARS) of collisions preventing. The results of applying the method for investigating in the processing of the RI of the road situation, obtained as a result of full-scale tests of the ARS model, are presented. Road objects radar signature statistical characteristics are analyzed. Analysis of the stability and racursal dependence of the radar portraits of road objects shows that the results of the analysis can be used to classify these objects.

Sergei Sokolov
Architecture of vision systems with several fields of view as a part of information support of mobile systems
S.M. Sokolov and A.A. Boguslavsky
Keldysh Institute of Applied Mathematics Russian Academy of Sciences (KIAM RAS), Moscow, Russia

The unified program architecture of real time vision system (VS) with several fields of view construction is described. The offered architecture provides both on-board and stationary usage. In case of stationary usage, it provides determination of location and trajectory of objects movement in the ordered system of co-ordinates. Principles of open architecture, componential technology and use of standard network decisions allow reconstructing operatively the unified architecture for the decision of specific tasks. The mutual binding of fields of view is important at formation of distributed VS uniform information field. For real time mobile systems time necessary for a rebinding and calibration is principal. The special attention also is paid to this part of the software. Orientation to use COTS technology at configuration of the system hardware allows generated VS to remain within the limits of economic feasibility. Examples of configurations concrete VS, created on offered architecture and results of experiments with them are resulted.

Carmen Vázquez Garcia
Temperature sensing using optical fibers for harsh environments
C. Vázquez1, A. Tapetado1, P.J. Pinzón1, D.S. Montero1, J.D. López-Cardona1, P. Contreras1, and J. Zubia2
1Electronics Technology Department, Carlos III University, Madrid, Spain
2Department of Electronics and Communications, Universidad País Vasco, Spain
Temperature is a major magnitude that needs to be measured in many different scenarios such as monitoring the temperature during manufacturing process, in aeronautical engine performance, or in all electrical aircraft batteries performance among others. Fiber optic temperature sensors have very interesting properties due to its potential to provide electromagnetic interference immunity, light weight, intrinsically safe nature, and depending on the technology high temperature range and remote operation. In this talk we will review our recent progress on intensity fiber-optic temperature sensing with different technologies and applications.

Joseba Zubia
Polymer optical fiber sensors for aircraft structural and engine health monitoring
J. Zubia, I. García, J. Villatoro, M. A. Illarramendi, J. Mateo, and C. Vázquez
Department of Communications Engineering, University of the Basque Country UPV/EHU, Bilbao, Spain

Aircraft structures and engines require periodic, scheduled inspection and maintenance operations. Such operations are time-consuming, labor intensive and a cost factor to the operations of commercial and defense aircraft fleets. Structural health monitoring (SHM) is a cost-effective approach to meet operational requirements, and to reduce maintenance costs in aircrafts. Polymer fiber optic sensor (PFOS) technology is a mature technology that provides advantages over traditional sensors, and can be used to monitor physical parameters not only of wing surfaces and fuselage sections but also of the engines themselves. Several practical SHM applications for aircraft structures and engines using PFOS will be reviewed in this talk, such as impact detection and location, strain, temperature and deformation measurements on composite structural elements made of carbon fiber-reinforced plastic (CFRP) materials.  With regard to engine condition evaluation, we will show some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in an engine turbine assembled in a wind tunnel and for turbine pressure with a Fabry-Perot fiber interferometer. The reliability of the results in the turbine rig testing facilities suggests the possibility of performing these measurements in real turbines under real working conditions.

DACINT invited presentations: 

Guilhem Almuneau
Vertical integration of an electro-absorption modulator in a VCSEL device
L. Marigo-Lombarta2, A. Arnoult1, C. Viallon1, S. Calvez1, A. Lecestre1, B. Reig1, A. Rumeau1, H. Thienpont2, K. Panajotov2, and G. Almuneau1
1LAAS - CNRS, Université de Toulouse, France
2Department of Applied Physics and Photonics (TW-TONA), Vrije Universiteit Brussel, Belgium

The huge increase of datacom traffic requires laser sources of ever-widening modulation bandwidth. Vertical-Cavity Surface-Emitting Lasers (VCSEL) are strategically relevant given that their wide use for short communication links such as in datacenters and are, in light of recent developments, good candidates to address such demands. We propose to increase the modulation bandwidth by vertically integrating a continuous-wave VCSEL with an high-speed electroabsorption modulator (EAM-VCSEL). We will present our studies on the electrical and optical designs, on the development of optimized fabrication steps and on the microwave characterizations leading to the realization of integrated EAM-VCSEL devices.

Nikos Bamiedakis
Flexible multimode polymer waveguides for versatile high-speed optical interconnects
N. Bamiedakis, F. Shi, D. Chu, R.V. Penty, and I.H. White
Electrical Engineering Division, Engineering Department, University of Cambridge, UK
In this work, the loss and bandwidth performance of flexible multimode polymer waveguides are investigated under different launch conditions. It is shown that bending excess loss below 2 dB is achieved for radii larger than 3 mm for a 50 µm MMF input, and twisting excess loss below 0.6 dB for up to 1 full 360-degree turn even for a relatively overfilled launch. The bandwidth studies reveal that bending the waveguides does not significantly impact their bandwidth performance, with bandwidth-length product values in excess of 150 GHz×m recorded for the launch conditions studied.

Guido Belfiore
25 Gbit/s adaptive 3-tap FFE VCSEL driver in 28-nm CMOS for data center communications
G. Belfiore, L. Szilagyi, R. Henker, and F. Ellinger
Chair of Circuit Design and Network Theory, Technische Universität Dresden, Germany
This paper presents the design and measurement of an adaptive 3-tap feed-forward equalizer (FFE) integrated circuit (IC) manufactured in 28-nm digital bulk CMOS technology. The driver consumes only 100 mW from a single 1.5 V supply including the vertical-cavity surface-emitting laser (VCSEL) and excluding the input matching circuitry. The 50 Ω input baluns, necessary only for the measurement, are not power optimized and consume 60 mW. The driver was assembled on a printed circuit board (PCB) with DC connections and bonded to a commercially available 7.5 GHz VCSEL diode. An error-free (BER<10-12) optical transmission with a data rate (DR) of 25 Gbit/s was achieved. It is proven that the 3‑tap FFE improves the quality of the optical eye diagram at a cost of eye amplitude. When not needed, the circuitry of the FFE can be switched off saving 22.5 mW of power.

Yossef Ben-Ezra
Applications of quantum dot (QD) lasers in optical communication for datacenters
Y. Ben Ezra1,2,  B.I. Lembrikov1, and S. Zarkovsky1,2
1Faculty of Electrical Engineering and Electronics, Holon Institute of Technology, Israel
2MER Cello, Holon, Israel

Optical communication technologies are the best solutions for the high-performance computing infrastructures (HPCs) and datacenter networks (DCNs). All-optical approach consists of switching all data at the packet in the optical domain which requires data rates higher than 100 Gbit/s. The quantum dot (QD) lasers are the promising candidates for such applications due to their high operation rates, light generation at the wavelengths of 1.33 μm and 1.55 μm, and low injection currents. We investigated theoretically the modulation process of the optically injected QD laser placed in a DCN for advanced modulation format PAM-4. The numerical simulation results show that the DCN performance significantly improves due to the optical synchronization of the QD laser carrier dynamics.

Christophe Finot
Titanium dioxide waveguides for data transmissions at 1.55 and 2 µm
M. Lamy, K. Hammani, J. Arocas, J. Fatome, J-C. Weeber, and C. Finot
Université de Bourgogne, Besançon, France

We demonstrate error free transmissions of 10 Gbps signals in titanium dioxide waveguides at wavelengths of 1.55 or 2 µm. An efficient coupling of light is achieved thanks to metal grating couplers and we have checked that the component could be used with standard CWDM SFP+ devices.

Ronny Henker
Adaptive high-speed and ultra-low power optical interconnect for data center communications
R. Henker1, T. Toifl2, A. Cevrero2, I. Oezkaya2, M. Georgiades3, M. Khafaji1, J. Pliva1, and F. Ellinger1
1Technische Universität Dresden, Chair of Circuit Design and Network Theory, Dresden, Germany
2IBM Research GmbH, Zurich Research Laboratory, Rueschlikon, Switzerland
3PrimeTel PLC, Limassol, Cyprus
In this paper, two basic methods for a performance and power adaptivity on system and component level in optical interconnects for data center communications are introduced and explained. The approaches are investigated in the EC FP7 project ADDAPT (Adaptive Data and Power Aware Transceivers for Optical Communications) which targets significant power savings in optical interconnects. First, a rapid link on/off switching is investigated when idle symbols are present in the data stream. For active data, a rapid on-switching in less than 20 ns at data rate of 56 Gb/s is achieved, which is almost one order of magnitude faster than in current systems. To evaluate power savings potential in links with multiple lanes, network analyses were performed and several packet statistics were investigated. As a result, up to 80% power savings can be achieved at 10% link utilization. Second, dynamic speed adaptation allows scaling down the performance of individual link system according to varying network traffic load. By this adaptive tuning, a reduction of the nominal power consumption by up to 80% is estimated when tuning down the link data rate from 56 Gb/s to 7 Gb/s.

Kambiz Jamshidi
Design considerations and constraints in silicon based optical on-board interconnects for short range communications
M. Catuneanu1, R. Henker2, R. Hosseini1, M. Jazayerifar1, H. Aminpour1, D. Schöniger2, A. Giuglea2, K. Nieweglowski3, F. Ellinger2, K. Bock3, and K. Jamshidi1
1Integrated Photonics Devices Group, TU Dresden, Germany
2Chair of Circuit Design and Network Theory, TU Dresden, Germany
3Institute of Electronic Packaging Technology, TU Dresden, Germany

In this paper, various trade-offs for the design of short-range optical interconnects for on-board communication in a high-performance computer (HPC) will be discussed. Energy consumption and bandwidth requirements of the components, which are used for the realization of an optical link in future highly adaptive energy-efficient computers, will be estimated based on the energy consumption and bandwidth trends of super computers. A scalable solution and its performance in terms of energy efficiency and bandwidth will be discussed. Results regarding all sub-components of such an optical on-board link are presented including optical components, packaging, and electrical components will be presented in the paper.

Nikolay Ledentsov
Progress in design and development of anti-guiding vertical cavity surface emitting laser at 850 nm: Above 50 Gb/s and single mode
N.N. Ledentsov1, V.A. Shchukin1, V.P. Kalosha1, N.N. Ledentsov Jr.1,2, J-R. Kropp1, M. Agustin1, Ł. Chorchos2, and J.P. Turkiewicz2
1VI Systems GmbH, Berlin, Germany
2Warsaw University of Technology, Poland

Design of the oxide-confined vertical cavity surface emitting laser (VCSEL) with anti-guiding AlAs-rich core has recently attracted a lot of attention. Lack of the waveguiding core increases the oscillator strength of the VCSEL mode, allows the ultimate optical confinement (“λ/2 design”) and reduces dramatically the optical power accumulated in the VCSEL mesa in the regions outside of the oxide aperture. We consider basic differences of conventional and anti-waveguiding VCSEL and address optical modes in the device. Both Joule heat and heat generated by the free carrier absorption of the optical mode in the doped semiconductor layers and their impact on the refractive index profile are considered. We show that for typical regimes of the VCSEL design and operation absorption-induced heat exceeds by several times the Joule heat while the shape of the generated heated domains strongly differ. Modeling shows that current increase results in an increase in spectral separation of the fundamental and high-order transverse optical modes. Selection of the fundamental mode persists upon increase in injection current up to 10 mA at 5 µm aperture diameter. We report on data transmission experiments up to 160 Gb/s using single mode anti-waveguiding VCSELs.

Stefan Lischke
Monolithic photonic BiCMOS technology for high-speed receiver applications
S. Lischke1, D. Knoll1, C. Mai1, A. Awny1, G. Winzer1, M. Kroh1, K. Voigt2, and L. Zimmermann1
IHP GmbH, Frankfurt/Oder, Germany
2Technische Universität Berlin, Germany

Photonic-electronic integration is a key technology to master traffic growth and therefore an enabler of future network technologies. For some time now, a new silicon photonic-electronic integration technology is under development, photonics BiCMOS, which has met a lot of interest due to its unique properties. IHP’s photonic BiCMOS is a monolithic planar technology co-integrating on a single substrate high-speed RF frontend electronics – a fully featured SiGe:C BiCMOS – with high-speed photonic devices such as broadband germanium detectors, modulators, and SOI nano-waveguide integrated optics. Photonic BiCMOS is an electronic photonic integrated circuit (ePIC) technology. High-performance RF capabilities are enabled by heterojunction bipolar transistors (HBTs), which are integrated with 0.25 µm CMOS.  This contribution will review the integration of a key component, the germanium detector. The integration of germanium in the BiCMOS flow results in performance issues of electronic devices and of the germanium detector itself. We shall present measures to over-come detrimental integration effects and present examples of recent receiver demonstrators that indicate the potential for monolithic high-speed receivers at 1550 nm.

Chun-Nien Liu
Packaging high-coupling lasers to polarization maintaining fibers employing visual alignment
Chun-Nien Liu and Wood-Hi Cheng
Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung, Taiwan

A new scheme of oriented-dependence microlens (ODM) employing automatic grinding and precise fusing techniques to achieve high-average coupling efficiency and high- polarized extinction ratio from high-power 980-nm lasers into single mode fibers is presented. A practical package of laser/PMF with compact size and few components employing the ODM is also demonstrated. The proposed ODM with visually precise surface feature alignment to achieve both high coupling and polarization is beneficial for the application of laser/PMF modules for use in high-precision fiber optic gyroscopes and many high-performance and low-cost lightwave interconnections.

Roberto Llorente Sáez
Spatial division multiplexing in the short and medium range: From the datacenter to the fronthaul
R. Llorente, M. Morant, D. Garcia-Rodriguez, and J.L. Corral
Nanophotonics Technology Center, Universitat Politècnica de València, Spain

This paper reports the experimental performance of spatial division multiplexing (SDM) optical transmission systems. These SDM systems are intended to support key short- and medium-range low-latency applications as optical fronthaul in cellular networks, point-to-point optical backhaul and baseband optical links in datacentre applications. In particular, the experimental demonstration of optical fronthaul of 3GPP LTE-A wireless supporting up to 4×4 MIMO on a 4-core multicore fibre (MCF) is reported. The results indicate that successful multiple-antenna transmission is achieved at 150 m MCF range. SDM implementation in SSMF by modal multiplexing is a complementary approach to MCF and is also experimentally investigated. The key limiting factor in this case is the optical mode conversion stage. An efficient mode-conversion coupler is proposed and evaluated for 850 nm and 1550 nm operation. For 1550 nm, a coupler has been fabricated in silicon-on-insulator (SOI) technology. Few-mode transmission performance is analysed considering the propagation of two LP mode groups. The experimental results indicate that the SDM system is suitable for short-range datacentre applications operating at 850 nm where integration capability is of great importance, and medium-range point-to-point optical backhaul links operating at 1550 nm can also benefit from the proposed device architecture.

Íñigo Molina-Fernández
Broadband and high-performance devices for the silicon and silicon-nitride platforms
I. Molina-Fernández1, R. Halir1, A. Ortega-Moñux1, J.G. Wangüemert-Pérez1, Yang Chen2, Jian-Jun He2, P. Cheben3, J.H. Schmid3, T. Domínguez Bucio4, A.Z. Khokhar4, M. Banakar4, K. Grabska4, and F.Y. Gardes4
1E.T.S.I. Telecomunicación, Universidad de Málaga, Spain
2State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, China
3National Research Council Canada, Ottawa, Ontario, Canada
4Optoelectronics Research Centre, University of Southampton, UK

The increasing demand for higher data rates and small form factor equipment for optical networks is fuelling research on integrated optical devices with small footprint and broad bandwidth. Here, we present novel design approaches for grating couplers in the silicon and silicon nitride platforms that enable broadband operation and highly efficient coupling. Furthermore, we report experimental findings on compact integrated waveguide splitters that provide virtual perfect performance over more than 300 nm of bandwidth at telecom wavelengths.

Bert Offrein
CMOS-embedded lasers for advanced silicon photonics devices
M. Seifried, H. Hahn, G. Villares, F. Horst, D. Caimi, C. Caër, Y. Baumgartner, M. Sousa, R. Dangel, L. Czornomaz, and B.J. Offrein
IBM Research – Zurich, Switzerland

Realizing CMOS-compatible integrated lasers on silicon is a crucial step towards cost-efficient, high-functional optoelectronic integrated circuits (OEICs). Here, we report on a concept to embed active optical devices based on a bonded III-V epitaxial layer stack between the FEOL and BEOL of a CMOS silicon photonics chip. Ultra-shallow laser devices are realized with this concept and optically-pumped lasing, coupled to silicon is demonstrated for the first time with such a concept.

Oskars Ozolins
Optical spectral reshaping for directly modulated 4-pulse amplitude modulation signals
O. Ozolins1, F. Da Ros2, V. Cristofori2, Xiaodan Pang1,3, R. Schatz3, M.E. Chaibi4, L. Bramerie4, S. Popov3, M. Galili2, L.K. Oxenløwe2, C. Peucheret4, and G. Jacobsen1
1ACREO Swedish ICT AB, Kista, Sweden
2DTU Fotonik, Technical University of Denmark, Lyngby, Denmark
3KTH Royal Institute of Technology, Stockholm, Sweden
4FOTON Laboratory, CNRS UMR 6082, ENSSAT, University of Rennes 1, Lannion, France

The tremendous traffic growth in intra/inter-datacenters requires low-cost high-speed integrated solutions [O. Ozolins et al., 100 GHz externally modulated laser for optical interconnects, J. Lightwave Technol., Invited paper, Preprint, 2017]. To enable a significantly reduced footprint directly modulated lasers (DMLs) have been proposed instead of large external modulators. However, it is challenging to use DMLs due to their low dispersion tolerance and limited achievable extinction ratio (ER). A promising solution to this problem is optical spectral reshaping (OSR) since it is possible to increase the dispersion tolerance as well as to enhance the achievable ER for both on-of-keying [V. Cristofori et al., Direct modulation of a hybrid III-V/Si DFB laser with MRR filtering for 22.5-Gb/s error-free dispersion-uncompensated transmission over 2.5-km SSMF, in ECOC, Düsseldorf, 2016, paper Th.2.P2.SC4.42] and 4-pulse amplitude modulation (PAM) [C. Yang et al., IM/DD-based 112-Gb/s/lambda PAM-4 transmission using 18-Gbps DML, IEEE Photon. J. 8, 1-7 (2016)] signals. However, moving to 4-PAM,many of the impressive demonstrations reported so far rely heavily on off-line digital signal processing (DSP), which increases latency, power consumption and cost. In this talk, we report on (i) a detailed numerical analysis on the complex transfer function of the optical filter for optical spectral reshaping in case of pulse amplitude modulation and(ii) an experimental demonstration of real-time dispersion-uncompensated transmission of 10-GBd and 14-GBd 4-PAM signals up to 10- and 26-km SSMF. This is achieved by combining a commercial 10-Gb/s DML with optical spectral shaping, thus removing the need for any complex off-line DSP and improving dispersion tolerance. These achievements are enabled by OSR based on a passive microring resonator fabricated on the SOI platform [F. Da Ros et al., 4-PAM dispersion-uncompensated transmission with micro-ring resonator enhanced 1.55-μm DMLin CLEO, California, USA, 2017, submitted]. Significant improvement in receiver sensitivities was observed for both a 10-GBd signal after 10-km SSMF transmission and 14-GBd with no penalty after 26-km SSMF transmission.

Liam O'Faolain
Athermal hybrid laser

L. O’Faolain and C. Devarapu
SUPA, School of Physics and Astronomy, University of St. Andrews, UK

Dense WDM in the datacentre will be the next frontier for datacentre interconnects. Current silicon based transceivers are based on a single spatial multiplexed Distributed Feedback laser (DFB) and external silicon modulators providing an effective but limited system. So far, wavelength division multiplexing (WDM) has seen a very slow uptake in data-centre interconnects due to issues in maintaining the laser output at a fixed wavelength in an environment in which the ambient temperature varies widely. We will present results on a hybrid laser that uses a silicon nitride based reflector. Silicon nitride has a much lower thermo-optic coefficient than indium phosphide or silicon and consequently the hybrid laser exhibits dramatically reduced sensitivity to temperature fluctuations.

Lorenzo Pavesi
Silicon photonics for optical switching in data centers
L. Pavesi, Department of Physics, University of Trento, Trento, Italy
A reconfigurable optical switching matrix able to route DWDM signals is presented. It is based on copper pillar interconnected electrical integrated and a photonic integrated circuits with more than thousands of different optical and electrical devices. The functional system is suitable to be used as a transponder aggregator in optical network or as an optical switch element in data centers.

Diego Pérez-Galacho
25 Gbit/s O-band push-pull Mach-Zehnder silicon modulator for datacom applications
D. Pérez-Galacho1, C. Baudot2, T. Hirtzlin1, N. Vulliet2, S. Messaoudène2, P. Crozat1, F. Boeuf2, L. Vivien1, and D. Marris-Morini1
1Centre for Nanoscience and Nanotechnology, CNRS, Univ. Paris-Sud, Univ. Paris-Saclay, Orsay, France
2STMicroelectronics, Crolles, France
Optical modulation in the O-Band using a Mach-Zehnder modulator in push-pull configuration is presented and experimentally demonstrated. Open eye diagrams at 25 GBps have been obtained with more than 8 dB extinction ratio with an active length of only 1 mm.

Nikos Pleros
Optical interconnect and memory components for disaggregated computing
G.T. Kanellos, S. Pitris, N. Terzenidis, C. Mitsolidou, T. Alexoudi, and N. Pleros
Department of Informatics, Aristotle University of Thessaloniki, Greece

High-performance server boards rely on multi-socket architectures for increasing the processing power density on the board level and for flattening the data center networks beyond leaf-spine architectures.  Scaling, however, the number of processors per board and retaining at the same time low-latency and high-throughput metrics puts current electronic technologies into challenge. In this article, we report on our recent work carried out in the H2020 projects ICT-STREAMS and dREDBox that promotes the use of Silicon Photonic transceiver and routing modules in a powerful board-level, chip-to-chip interconnect paradigm. The proposed on-board platform leverages WDM parallel transmission with a powerful wavelength routing approach that is capable of interconnecting multiple processors with up to 25.6 Tbps on-board throughput, providing direct and collision-less any-to-any communication between multiple compute and memory sockets at low-energy 50 Gbps OOK line-rates. We demonstrate recent advances on the Si-based WDM transceiver, cyclic AWGR router and polymer-based electro-optical circuit board key-enabling technologies, discussing also potential applications in disaggregated rack-scale architectures. We also demonstrate our recent research on optical RAM technologies and optical cache memory architectures that can take advantage of the on-board interconnect technology for yielding true disintegrated computing resolving both power and memory bandwidth bottlenecks of current computational settings.

Sergei Popov
High-speed optical interconnects with integrated externally modulated laser
O. Ozolins1, Xiaodan Pang1,2, M. Iglesias Olmedo2, A. Kakkar2, A. Udalcovs1, J.R. Navarro1, R. Schatz2, U. Westergren2, G. Jacobsen1, and S. Popov2
1ACREO Swedish ICT AB, Kista, Sweden
2KTH Royal Institute of Technology, Stockholm, Sweden

The cloud services together with the huge size datasets are driving demand for bandwidth in datacenters [R. Lin et al., Experimental validation of scalability improvement for passive optical interconnect by implementing digital equalization, ECOC 2016, pp. 812-814]. The 400 Gbps client-side links are demanding cost efficient solution: to reduce the number of lanes and increase the bandwidth for a single lane. The intensity modulation and direct-detection systems together with integrated semiconductor lasers and modulators appear as promising solution in four optical lanes at 100G since it reduces complexity, power consumption and costs [X. Pang et al., Evaluation of high-speed EML-based IM/DD links with PAM modulations and low-complexity equalization, ECOC 2016, paper W.4.P1.SC5.54]. However, it requires silicon and InP opto-electronic components with more than 70 GHz bandwidth [O. Ozolins et al., 100 GHz EML for high speed optical interconnect applications, ECOC 2016, paper M2.4.4]. In this talk, we report on a cost-efficient integrated externally modulated laser (EML) with high bandwidth for record high-speed intensity modulation and direct detection system demonstration with up to 100G OOK, PAM4/8 and duobinary signaling, as well as analog modulations e.g. DMT, paving the way for high speed multilevel modulation formats [M. Verplaetse et al., Real-time 100 Gb/s transmission using 3-level electrical duobinary modulation for short-reach optical interconnects, IEEE/OSA J. Lightwave Technol., doi.org/10.1109/JLT.2016.2643778], [O. Ozolins et al., 100 GHz EML for high speed optical interconnect applications, IEEE/OSA J. Lightwave Technol., doi.org/10.1109/JLT.2017.2651947], [X. Hong et al., 1.55-μm EML-based DMT transmission with nonlinearity-aware time domain super-Nyquist image induced aliasing, OFC 2017, paper Th3D.3]. Related techniques including digital signal processing algorithms for timing recovery, adaptive/static equalization are also discussed in terms of practical implementation and complexity. In addition, techniques constructively using time domain super-Nyquist image induced aliasing for mitigating modulator driver nonlinearity for high speed DMT transmission will be presented [A. Kakkar et al., Low complexity timing recovery algorithm for PAM-8 in high speed direct detection short range links, OFC 2017, paper W2A.54].

Danish Rafique
Digital pre-emphasis based system design trade-offs for 64 Gbaud coherent data center interconnects
D. Rafique1, N. Eiselt2, H. Griesser1, B. Wohlfeil2, M. Eiselt2, and J-P. Elbers1
1ADVA Optical Networking SE, Munich, Germany
2ADVA Optical Networking SE, Meiningen, Germany

We report on the role of digital pre-emphasis in facilitating 64 Gbaud DP-64QAM coherent optical systems based on currently available commercial 32 Gbaud transceiver components. In particular, we vary the extent of digital pre-emphasis together with digital-to-analog converter bandwidth and resolution, and show the optical back-to-back performance and transmitter output power trade-offs. Our results suggest that with a minimum required DAC bandwidth and effective number of bits of 25 GHz and 6 bits, respectively (at 1 dB penalty w.r.t best performance), an optimized DPE strength bandwidth of 18 GHz allows for a TX output power of -16 dBm, with an associated maximum OSNR penalty of ~3 dB, w.r.t. the theoretical bound for 64 Gbaud DP-64QAM.

Werner Rosenkranz
Flexible optical modulation technologies for data centre applications
S. Ohlendorf and W. Rosenkranz
Christian-Albrechts-Universität zu Kiel, Germany

Communication equipment for data center applications needs to be low-cost, energy-efficient and flexible in the sense that spectral efficiency, reach and complexity should be adjustable with a high degree of flexibility in the digital signal processing of the transceivers. We present and compare different flexible modulation formats like discrete multi-tone, time domain hybrid pulse amplitude modulation and multidimensional modulation in the environment of data centers. We use vestigial sideband transmission to avoid power fading and minimize the influence of signal-signal-beating interference by optimization of the optical signal to carrier ratio.

Lars Thylén
Integrated nanophotonics for information technologies and sensors: Ways to solve the present gridlock in performance
L. Thylén1,3, L. Wosinski2,3, X. Sun2,3, D. Dai3,4
1Dept. of Theoretical Chemistry and Biology, Royal Institute of Technology, Stockholm, Sweden
2Laboratory of Photonics and Microwave Engineering, Royal Institute of Technology (KTH), Kista, Sweden
3JORCEP [Joint Research Center of Photonics of Royal Institute of Technology (KTH) and Zhejiang University], Zhejiang University, Hangzhou, China
4Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, Zhejiang University, Hangzhou, China

The decades long development in shrinking footprint and improving performance of photonics integrated circuits has seemingly slowed down in recent years, posing problems in e.g. interconnects in data centers with their ever increasing power requirements. Thus, routes to a continued development towards smaller footprint, lower power, higher performance integrated nanophotonics will be presented and discussed. Comparison to some nanoelectronics devices will be made.

Ioannis Tomkos
Designing the next generation of intra- and inter-datacentres interconnects
V. Vgenopoulou, N. Raptis, E. Grivas, and I. Tomkos
Athens Information Technology (AIT), Marousi, Greece

In this work, we investigate the performance specifications of the components comprising the suggested intra- and inter-Data Centres (DCs) systems according to DIMENSION project. More specifically, we deal with the performance specifications of the laser sources and the respective modulators. The intra-DC system employs a novel Directly Modulated Laser (DML) grown on Silicon Photonics (SiPh) and targets links up to 10km. A coherent solution is selected for the inter-DC system that employs a carrier-depletion Mach–Zehnder Modulator (MZM) based on a SiGe Bipolar Complementary Metal-Oxide Semiconductor (BiCMOS) technology and targets links that exceed 80 km. In both systems, the considered aggregate data rate is 400 Gbit/s.

Jarosław Turkiewicz
High speed transmission with 850 nm SM and MM VCSELs
J.P. Turkiewicz1, Ł. Chorchos1, V.A. Shchukin2, V.M. Kalosha2, J-R. Kropp2, M. Augustin2, N. Ledentsov Jr2, and N.N. Ledentsov2
1Instytut Telekomunikacji, Politechnika Warszawska, Warsaw, Poland
2VI-Systems, Berlin, Germany

The ever growing data volumes in the IT infrastructure can only by carried by the optical transmission technologies. The key requirements for such transmission systems are the small footprint, high energy efficiency and the low cost of ownership. One of the most promising candidates to realize the energy efficient high speed transmission over the short distance is transmission with the multi-mode fibre and the 850 nm VCSELs. In this paper the transmission performance of the two types of the 850 nm VCSEL, namely single mode and multi-mode one is compared. Several key VCSEL transmission characteristics, like bandwidth of both VCSEL types were measured and evaluated. The transmission experiments in the various system configurations were performed at the bit rates up to 56 Gbit/s. The results demonstrate that the SM VCSEL outperforms MM VCSEL for longer distances and higher data rates.

Konstantinos Vyrsokinos
Optical packet forwarding and time rearrangement based on double wavelength conversion with SOA-MZI gates
K. Vyrsokinos, Department of Physics, Aristotle University of Thessaloniki, Greece
Data Centers (DC) are continuously expanding in size as data migrate to the cloud leading to an unparalleled growth of the traffic circulating in the DC network and reaching several Petabytes/s across the various levels in the fat tree architecture. Currently, handling and forwarding of the traffic is accommodated by electronic switches at each hop that consume several tens of pJ/bit taking into account the additional o-e-o conversions. Transferring this function entirely in the optical domain towards minimization of delay and power consumption is prohibitive given the lack of optical memory that is required to store the packets when contention resolution arise at each node. In this work we are presenting a packet forwarding scheme for contention resolution, where short optical packets are delayed to avoid collision through a double  wavelength conversions (WCs) setup. The first WC is defining the path delay, while the second one is restoring the original wavelength for maximization of channel capacity. The same setup is capable also to successfully rearrange in time packets from multiple input ports with less than 2.4 dB power penalty for 10Gb/s bit rate. In both setups the WC operation is achieved with Mach Zehnder Interferometers employing Semiconductor Optical Amplifier as nonlinear elements.

DCN invited presentations:

Ramon Aparicio-Pardo
A cost model for green fog computing and networking
R. Aparicio-Pardo and L. Sassatelli
Université Côte d'Azur, CNRS, Sophia Antipolis, Nice, France

The emergency of 4K and virtual reality contents will stress even more the future access/aggregation networks, where video contents have already become the main traffic contributor. The deployment at middle of the convergent access of near-user micro data-centres (DCs) nodes is one promising approach to successfully manage this challenge. These nodes will be responsible for switching enormous amounts of traffic and simultaneously performing heavy CPU tasks (such as video or radio baseband processing). Only a flexible management of these nodes based on NFV, SDN and data analytics will allow meeting these tasks. In this paper, we present a consistent and complete cost model collecting main tradeoffs between energy savings and CPU processing suitable to be used in such a flexible management framework.
Nicola Calabretta
OPSquare: Towards petabit/s optical data center networks based on WDM cross-connect switches with flow control
N. Calabretta, Fulong Yan, and Wang Miao
Institute for Photonic Integration (IPI) Research Institute, Eindhoven University of Technology, the Netherlands
Scaling the capacity while maintaining low latency and power consumption is a challenge for hierarchical data center networks (DCNs) based on electrical switches. In this work we present a novel optical DCN architecture called OPSquare that potentially addresses the scaling issues by employing parallel intra- and inter-cluster switching networks based on distributed fast WDM optical cross-connect (OXC) switches and a novel top-of-rack (ToR) switch architecture. The WDM OXC switches with nanoseconds reconfiguration time allow flexible switching capability in both wavelength and time domains and statistical multiplexing. Packet loss, latency, throughput, multi-path dynamic switching with flow control operation, and scalability will be discussed and experimentally evaluation by employing a 4×4 OXC prototypes. The potential of switching higher-order modulation and waveband signals further proves the suitability of OPSquare architecture for Petabit/s and low-latency DCN by using optical switches with moderate radix.
Jiajia Chen
Physical-layer network coding for passive optical interconnects in datacenter networks
Rui Lin, Yuxin Cheng, Ming Tang, Deming Liu, and Jiajia Chen
KTH Royal Institute of Technology, Stockholm, Sweden

We introduce physical-layer network coding for a passive optical interconnect architecture in datacenter networks. Results reveal that half of the wavelengths can be saved to obtain latency in the magnitude of microseconds.
Shanguo Huang
Agile and fine programmable optical interconnection provisioning in data center network
Shanguo Huang and Bingli Guo
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications (BUPT), China
Optical interconnection provisioning in Data Center (DC) draws lots of interests thanks to its high bandwidth and power efficiency. Optical TDM connection is an alternative solution to enable port sharing but with guaranteed bandwidth (like optical circuit connection). At the same time, since the throughput of traffic in DC is fluctuating through time, it is quite critical to adjust the TDM slot allocation dynamically according to the actual traffic demands. A DPDK-based online TDM allocator and a set of protocol will be introduced to handle elephant flow in data center.
Daniel King
The rise of the intent-driven data center fabric
D. King1, C. Rotsos1, G. Antichi2, and N. Georgalas3
1Lancaster University, UK
2Cambridge University, UK
3British Telecom, UK

Deployment of high-bandwidth Network Functions Virtualisation (NFV) using programmable optics-based data center networks (DCN) and DCN-interconnects, is increasing. However, limitations are appearing due to complex optical network configuration and operation. Application-to-network awareness and automation is required for future high-bandwidth low-latency NFV-based services. The ability for application orchestrators to query current network conditions and issue “Intent” requests – automated policy-based connection demands across DCN infrastructure – will be critical for next generation Cloud, 5G and Mobile Edge Computing. Our paper has identified key network operator use-cases. We detail the limitations of managing optical DCN infrastructure for services using existing programmable control solutions. Finally, we outline the key requirements, architecture, function, and research opportunities, to achieve intent-driven optical networking.

Christos Spatharakis
Slotted TDMA and optically switched network for disaggregated datacenters
K. Tokas1, I. Patronas1,2, C. Spatharakis1, D. Reisis1,2, P. Bakopoulos1, and H. Avramopoulos1
1Photonics Communications Research Laboratory, National Technical University of Athens, Greece
2Electronics Laboratory, Faculty of Physics, National and Kapodistrian University of Athens, Greece
The relentless traffic growth in datacenter networks is stimulating the adoption of pioneering optical interconnect technologies as well as their integration with novel network and switching architectures. Even more, the need for disaggregation of data storage and processing resources significantly increases the capacity and dimensioning requirements of such networks. In this context, a novel datacenter network architecture that combines space and wavelength switching functionalities is demonstrated experimentally. The architecture leverages slotted TDMA/WDM switching to realize dynamic resource allocation with sub-wavelength granularity, thus realizing a low cost and power consumption, scalable datacenter network. Dynamic reconfiguration of the slotted network vouches for low latency operation of the data plane and hence, it fulfils the requirements of the envisaged disaggregated datacenter infrastructure. The current paper reports the experimental evaluation of the optical subsystems and demonstrates the proof of concept for combined space- and wavelength-switching with optical bursts of 200 μs duration in different network scenarios. The generation and reception of slotted traffic, as well as the control of the optical switching subsystems is performed by means of addressable FPGA boards.

Emmanouel Varvarigos
Resource partitioning in the NEPHELE datacentre interconnect
K. Yiannopoulos1, K. Kontodimas2, K. Christodoulopoulos2,3, and E. Varvarigos2
1Department of Informatics and Telecommunications, University of Peloponnese, Greece
2School of Electrical Engineering and Computer Science, National Technical University of Athens, Greece
3Department of Computer Engineering and Informatics, University of Patras, Greece

We present heuristic algorithms for the efficient resource partitioning in the NEPHELE datacentre optical interconnect. The algorithms aim to segment the network into smaller and isolated virtual datacentres (VDCs), where all racks are able to communicate at full capacity irrespective of their placement. Since the NEPHELE architecture relies on shared optical rings, the isolation of VDC traffic is challenging. Observing its close resemblance to finding a bi-clique on a bipartite graph, which is NP-hard, we propose heuristic algorithms which find a solution by limiting either the spatial spread of racks that construct each VDC or their wavelength allocation. If a solution cannot be found, then the algorithms invoke a second de-fragmentation phase, where they re-allocate the racks of existing VDCs to concentrate them spatially and reduce traffic on the shared optical rings. It is demonstrated via simulation that the proposed heuristics can achieve very high utilization and also exhibit low VDC request blocking probability for typically expected VDC sizes.

ESPC invited presentations: 

Foued Amrani
Deep-UV plasma emission in hollow-core photonic crystal fiber
F. Amrani1, F. Delahaye1, B. Debord1, L. Lemos Alves2, F. Gérôme1, and F. Benabid1
1GPPMM group, Xlim Research Institute, UMR CNRS 7252, University of Limoges, France
2Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Portugal

In this paper, after reviewing results in the emerging plasma photonics field, we report on a strong plasma emission in the Deep-UV (DUV) range using gas mixture for development of a tunable and miniaturized UV radiation source using microwave-driven plasma-core photonic crystal fiber. Several spectral lines in DUV were produced by Ar-N2-O2 plasmas and tailored by simply varying the gas ratio of this gas mixture. In addition, a planar technology was used to develop a special ring excitator for compact solution to sustain efficiently such plasmas with microwave power as low as the Watt-level.

Toshihiko Baba
On-chip auto-correlator using counter propagating slow light in photonic crystal waveguide with TPA-PD array
T. Baba and K. Kondo
Yokohama National University, Japan

We propose an ultra-compact solid-state auto-correlator fabricated by Si photonics technology. The correlation waveform is obtained by detecting the overlap of two slow-light pulses counter-propagating in a photonic crystal waveguide integrated with two-photon absorption photodiode array. Since the device does not need a mechanical delay scanner, the full integration on a silicon-on-insulator, easy operation and high reliability are available. Different from conventional single-shot auto-correlators, it shows a much higher sensitivity for low-power pulses owing to the strong confinement and nonlinear enhancement of slow light. We succeeded in acquiring the auto-correlation waveform of pico-second pulses. The detection limit evaluated from the product of peak and average powers was of the order of 10−7 W2, which is equal to or even better than that of the commercial auto-correlators and 107 times better than the single-shot one’s.

Yu-Chieh Cheng
Flat focusing mirrors with two-dimensional chirped photonic crystals
Y.C. Cheng1,  J.H. Tsai1,  B.Z. Huang1, C. Cojocaru2,  J. Trull2,  R. Vilaseca2, and K. Staliunas2,3
1Department of Electro-Optical Engineering, National Taipei University of Technology, Taiwan
2Universitat Politècnica de Catalunya, Physics Department, Terrassa, Barcelona, Spain
3Institució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain

Flat focusing mirrors without any optical axis have been investigated by two-dimensional chirped photonic crystals. The principle of flat focusing mirror is similar to Veselago flat lens, which allows the beam focusing in the near field. The key idea of 2D chirped PhCs is to provide anomalous diffraction that can restrain a beam spreading and even focus a divergent beam upon reflection. Different focusing phenomena of the three 2D PhCs are shown in this paper and importantly, all of them have transversal invariance (lack of an optical axis).

Il-Sug Chung
Reciprocal-space engineering of quasi-bound states in the continuum in photonic crystal slabs for high-Q microcavities
Il-Sug Chung and A. Taghizadeh
Technical University of Denmark, Lyngby, Denmark

The bound states in the continuum (BICs) in photonic crystal (PhC) slabs presume infinite periodicity in the in-plane direction. Thus, a large number of unit cells are typically required to implement the BICs with a high quality (Q) factor. Here, we report on a method to engineer the reciprocal-space properties of BICs, which enables to keep the effect of the BIC phenomenon strong even for a microcavity of a few unit cells. For example, based on this method, a 3D microcavity of 4 unit cells can attain a Q factor of 18k. This allows for various BIC studies in a very compact platform, as well as novel functionalities for many important applications.

Crina Cojocaru
Domain statistics analysis of random nonlinear crystals via second harmonic generation
B. Wang1,4, C. Cojocaru1, W. Krolikowski2,3, K. Switkowski3,5, Y. Sheng2, H. Akhouayri4, R. Vilaseca1, M. Scalora6, and J. Trull1
1Universitat Politècnica de Catalunya, Physics Department, Terrassa, Barcelona, Spain
2Australian National University, Canberra, Australia
3Texas A&M University at Qatar, Doha, Qatar
4Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, France
5Warsaw University of Technology, Warsaw, Poland
6Charles M. Bowden Research Center, AMRDEC, RDECOM, Redstone Arsenal, USA

We demonstrate a non-destructive and indirect optical method for the characterization of ferroelectric domain size and distribution based on the analysis of the second harmonic spatial distribution. This method is based on a combination of experimental measurements and numerical simulations and allows obtaining information of domain statistics in disordered structures via the analysis of wavelength dependence of the angular second harmonic diffraction pattern.

Niels Gregersen
Comparison of five computational methods for computing Q factors in photonic crystal membrane cavities
A. Novitsky, J. Rosenkrantz de Lasson, L. Hagedorn Frandsen, P. Gutsche, S. Burger, O.S. Kim, O. Breinbjerg, A. Ivinskaya, Fengwen Wang, O. Sigmund, T. Häyrynen, A. Lavrinenko, J. Mørk, and N. Gregersen
DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Lyngby, Denmark

We benchmark five state-of-the-art computational methods by computing quality factors and resonance wavelengths in photonic crystal membrane L5 and L9 line defect cavities. The convergence of the methods with respect to resolution, degrees of freedom and number of modes is investigated. Special attention is paid to the influence of the size of the computational domain. Convergence is not obtained for all methods, indicating that some are more suitable than others for analyzing line defect cavities.

Romuald Houdré
Demonstration of continuous-wave second and third harmonic generation in high-Q gallium nitride photonic crystal cavities
M.S. Mohamed1, A. Simbula2, J-F. Carlin1, M. Minkov1, D. Gerace2, V. Savona1, N. Grandjean1, M. Galli2, and R. Houdré1
1Institut de Physique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
2Dipartimento di Fisica “A. Volta,” Università di Pavia, Italy

Wide bandgap semiconductors such as gallium nitride (GaN) are essential constituents of future optical circuits, as their optical response can accommodate a broad wavelength range while suppressing two-photon absorption and free-carrier absorption effects that are encountered with silicon (Si) structures. Their direct wide bandgap is also favourable for the incorporation of active elements. Furthermore, nonlinear optical processes can be harnessed by exploiting the higher-order susceptibility tensors of the crystal structure to achieve advanced light control modalities, enabling all-optical processing and the generation of entangled photon states. We will report on nonlinear frequency conversion from the telecom range via second harmonic generation (SHG) and third harmonic generation (THG) in suspended gallium nitride slab photonic crystal (PhC) cavities on silicon, under continuous-wave resonant excitation. Genetic optimization is applied to sweep parameter space for the highest cavity quality factors, and simultaneously accounting for power in-coupling. While there is a clear trade-off theoretically between coupling efficiency and Q-factor for a given cavity design, the upper limit on the Q-factor that is imposed by loss channels, given the disorder figure of current fabrication technology, makes room for introducing improved far-field coupling to enhance nonlinear processes without sacrificing the experimentally achievable light confinement. Far-field coupling is addressed through various PhC cavity designs, which enable the excitation of the fundamental mode with a Gaussian beam. Optimized two-dimensional PhC cavities with increased far-field coupling have been characterized with quality factors as high as 44'000, approaching the computed theoretical values. The strong enhancement in light confinement has enabled second harmonic generation (SHG) under continuous-wave excitation, with up-conversion from both 1300 nm and 1550 nm wavelength bands, confirmed by spectral and power dependence measurements. At 1550 nm, normalized SHG conversion efficiency as large as 2.4×10-3 W-1 are measured as well as simultaneous THG. SHG emission power of up to 0.74 nW has been detected without saturation.

Hamza Kurt
Light localization and filtering in three dimensional photonic structures
Z. Hayran1, K. Staliunas2,3, and H. Kurt1
1Nanophotonics Research Laboratory, Department of Electrical and Electronics Engineering, TOBB University of Economics and Technology, Ankara, Turkey
2DONLL, Departament de Física, Universitat Politècnica de Catalunya (UPC), Terrassa, Spain
3Institució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain

There dimensional photonic structures specifically, woodpile photonic crystals, have great potential for manipulating light propagation such as localization and filtering. Efficient harvesting of the energy of the incident photons require spatially localized waves interacting strongly with the absorbing material. Meanwhile, one can also utilize similar concept in order to implement filtering of light via defining drop channels that are linked with the main waveguide. One unique property of the woodpile photonic crystals is the complete band gap feature that may reduce the out-of-plane losses. Besides, band gap width and edges can be tuned by modifying three-dimensional woodpile photonic crystals into chirped one. In the present work, we show light localization via “rainbow trapping” concept and propose a drop-out mechanism based on the enhanced interaction between a defect waveguide and defect micro-cavities. Frequency resolved light detection/absorption and filtering capabilities are important in photodetector applications, optical communication, and solar energy.

Gregory Morozov
Semiclassical coupled wave theory for one-dimensional PT-symmetric photonic crystals
G.V. Morozov1, D.W.L. Sprung2, and J. Martorell3
1Scottish Universities Physics Alliance (SUPA), Institute of Thin Films, Sensors and Imaging, University of the West of Scotland, Paisley, UK
2Department of Physics and Astronomy, McMaster University, Hamilton, Canada
3Departament de Fisica Quantica i Astrofisica, Facultat de Fisica, University of Barcelona, Spain

Semiclassical coupled wave theory (SCWT) is applied to optical waves in one-dimensional PT-symmetric photonic crystals. In particular, the theory is used to calculate the bandgaps and reflectance/transmittance of such crystals. The results are in good agreement with exact numerical simulations based on the transfer matrix method.

Pablo Postigo
Optical coupling of double L7 photonic crystal microcavities for applications in quantum photonics
P.A. Postigo1, I. Prieto1,2, L.E. Muñoz-Camúñez1, and J.M. Llorens1
1IMM–Instituto de Microelectrónica de Madrid (CNM–CSIC), Madrid, Spain
2Laboratory for Solid State Physics, ETH Zürich (ETHZ), Switzerland

Coupled photonic crystal microcavities have been considered when exploring platforms for quantum photonic effects like quantum-optical Josephson interferometers, single photon emitters and coupled-cavity single-photon emitters and many others. Arrays of photonic cavities are relevant structures for developing large-scale photonic integrated circuits, single mode coupled-cavity lasers and for investigating basic quantum electrodynamics phenomena due to the photon hopping between interacting nanoresonators. In this work we have measured the emission of two L7 microcavities when their separation is varied. We have found optical coupled modes more clearly defined at specific cavity separations. Finally, we have simulated the optical mode distribution of the coupled system using the GME method, finding a good agreement between experiment and theory.

Kestutis Staliunas
Photonic crystal microchip laser
D. Gailevicius1, V. Koliadenko2, V. Purlys1, M. Peckus1, V. Taranenko2, and K. Staliunas3,4
1Laser Research Center, Vilnius University, Lithuania
2Institute of Applied Optics, NAS of Ukraine, Kyiv, Ukraine
3Dep. de Física, Universitat Politècnica de Catalunya, Terrassa, Spain
4ICREA, Barcelona, Spain

The microchip lasers, being sources of coherent light, suffer from one serious drawback: low spatial quality of the beam, strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here we propose that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. We experimentally show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by factor of 2, and thus increase the brightness of radiation by a factor of 4. This comprises a new kind of laser, the “photonic crystal microchip laser”, a very compact and efficient light source emitting high spatial quality high brightness radiation.

Alejandro Yacomotti
Long-tailed superthermal light as a quenching process in coupled photonic-crystal nanolasers
M. Marconi1, J. Javaloyes2, P. Hamel1, F. Raineri1, A. Levenson1, and A.M. Yacomotti1
1Center for Nanoscience and Nanotechnology (CNRS/C2N), Marcoussis, France
2Departament de Física, Universitat de les illes Baleares, Mallorca, Spain

We experimentally and theoretically investigate the superthermal photon statistics in evanescently, strongly coupled nanolasers. The nanolasers are fabricated in suspended 2D Photonic Crystal membranes, and studied as a function of short pulse-pump power. Such a non-stationary (transient) regime leads to a new route for the generation and control of long tailed superthermal light,  e.g. a light source with intensity fluctuations larger than those of thermal states. We analyze the heavy-tailed photon distributions (super-exponential) of the nonlasing (symmetric, in-phase) mode. We link, using a mean field model, both the emergence of the heavy tails and the superthermal nature of the emission. We show that passing through the lasing threshold corresponds to an abrupt decrease of the contribution of spontaneous emission —that plays the role of an effective temperature — during which the statistics of the nanolaser trajectories in phase space are dominated by transport instead of diffusion. In this sense, our photonic system can be regarded as a "quenching process". Changing the duration of this out-of-equilibrium quenching phase, one obtains long-tailed distributions for the unstable in-phase mode in agreement with the experimental results.

Fei Yu
Low loss anti-resonant hollow-core fibers and applications
Fei Yu and J.C. Knight
Centre for Photonics and Photonic Materials, Department of Physics, University of Bath, UK

This paper reviews the recent development of anti-resonant hollow-core fibers (AR-HCFs) and their applications. Such fibers have been shown to offer low-loss transmission windows which greatly extend the traditional spectral regions of hollow-core fibers into UV and mid-IR. The single mode performance, large mode area, low dispersion and nonlinearity naturally make AR-HCF the most promising medium for high-power short-pulse laser transmission for scientific and industrial applications. Meanwhile, low loss AR-HCF provides many meters of interaction length as a gas cell and greatly reduces the threshold of the stimulated light-gas interaction. Several laser-pumped AR-HCF gas laser systems have been demonstrated in the mid-IR region. Fiber-enhanced gas nonlinearity would be expected to provide more possibilities of wavelength conversion and novel optical phenomena in future.

EU-P invited presentations:

Ernesto Ciaramella
Design and characterization of the optical layer of a novel pair of underwater VLC modems
G. Cossu, A. Sturniolo, A. Messa, and E. Ciaramella
Scuola Superiore Sant’Anna, Istituto TeCIP, Pisa, Italy
We report on the design and experimental characterization of a novel underwater modem pair. We report on the design and experimental characterization of a novel pair of underwater wireless optical modems. Each of them is equipped with a blue LED array as transmitter, an APD photodiode as receiver and a pin photodiode for optical power monitoring. The modems are designed to operate at 10 Mbit/s (10BaseT Ethernet, Manchester-coded signal) in harsh conditions, i.e. in turbid water and with strong sunlight. Successful lab experiments and final sea tests confirm the validity of our approach.

Roberto Gaudino
Final system results from the EU FP7 project FABULOUS
S. Straullu1, S. Abrate1, V. Ferrero2, and R. Gaudino2
1ISMB, Istituto Superiore Mario Boella, Torino, Italy
2Politecnico di Torino, Italy

In the framework of the EU-funded research project “FABULOUS” we experimentally demonstrate an innovative FDMA-PON architecture whose upstream transmission is based on a reflective Mach-Zehnder modulator, reaching an overall upstream capacity of 32 Gbps per wavelength over 31 dB ODN loss in several previously published experiments targeting 1 Gbps per user and using 16-QAM as a modulation format. In this paper, we focus on the experimental demonstration of the flexibility of our system to a variety of different working conditions, targeting higher bit-rates per user (up to 10 Gbps) and different modulation formats.

Paola Parolari
RSOA-based self-seeded transmitters: The ERMES project results and offsprings
P. Parolari, M. Brunero, A. Gatto, and M. Martinelli
Politecnico di Milano, PoliCom - Dip. Elettronica Informazione e Bioingegneria, Milano, Italy

The EU FP7 ERMES project focused on the development of a wavelength division multiplexed passive optical network (WDM PON) colourless self-tuning transmitter based on reflective semiconductor optical amplifiers (RSOAs) self-seeding. These transmitters represent low cost solutions to achieve self-organized wavelength access networks. The EU ERMES project developed self-tuning transmitters both in the C- and O- band with tens of kilometres reach up to 10 Gb/s. During the project we developed different self-seeding architectures with single RSOA exploitation (standard self-seeding) or two-RSOA exploitation (amplified or face-to-face self-seeding). The employment of Faraday rotators and mirrors in retracing configurations ensured polarization insensitive operation of the self-seeded architectures allowing for the exploitation of high gain C and O-band RSOAs, which present a very high polarization dependent gain. The project evaluated the coexistence of time division multiplexing (TDM) and WDM PON supporting high-numbers of users: although the burst mode operation was limited by the build-up time of the long-cavity laser, the rise time is compatible with a sleep mode for energy saving. After the project conclusion self-seeded transmitters have been exploited with alternative modulation formats including polarization division multiplexing and frequency division multiplexing in order to increase the achievable bit rates. Finally further studies to increase modulation cancellation inside self-seeded transmitters have been performed.

Mario Rannello
Field-trial of a λ-to-the-user high-budget PON using a novel class of low-cost coherent transceivers and compatible with EPON system operation
M. Rannello1, I.V. Cano2, J. Tabares2, J.C. Velásquez2, S. Ghasemi2, V. Polo2, G.Y. Chu2, J. Prat2, R. Pous3, G. Azcárate3, C. Vilà3, H. Debrégeas4, G. Vall-llosera5, A. Rafel6, M. Artiglia1, F. Bottoni1, M. Presi1, and E. Ciaramella1
1TeCIP Institute, Scuola Superiore Sant’Anna, Pisa, Italy
2Universitat Politecnica de Catalunya (UPC), Barcelona, Spain
3Promax, L'Hospitalet de Llobregat, Spain
4III-V Lab, joint laboratory of Nokia Bell Labs, Thales Research and Technology, and CEA Leti, Palaiseau, France
5Ericsson Research, Stockholm, Sweden
6BT Technology Service & Operations, Ipswich, UK
COCONUT project demonstrated an innovative DWDM Passive Optical Network implementing the full λ‑to‑the‑user concept in a filterless distribution fiber network. We make use of an innovative class of coherent transceivers, that exploit the advantages of coherent detection in terms of sensitivity and channel selectivity in a cost efficient manner. The different transceivers developed target different use case scenarios, showing perfect compatibility with legacy infrastructures installed. In this paper, we report the successful trial of the proposed system in a testbed where 4 different coherent transceivers (plus one legacy E-PON system) ran simultaneously, operating over 14 DWDM channels, in a dark-fiber network in the city of Pisa, delivering real-time and/or test traffic. The testbed demonstrated filterless operations, multi-rate transmission (from 1.25 to 10 Gb/s/λ), high ODN loss (1840 dB) as well as a bi-directional channel monitoring system.

Marco Ruffini
End-to-end network design and experimentation in the DISCUS project
D.B. Payne, A. Arbelaez, R. Bonk, N.J. Doran, M. Furdek, R. Jensen, N. Parsons, T. Pfeiffer, L. Quesada, C. Raack, G. Talli, P. Townsend, R. Wessäly, L. Wosinska, X. Yin, and M. Ruffini
CTVR, Trinity College Dublin, Ireland
This paper reports on the overall outcome of the FP7 DISCUS project, which aimed at designing end to end architectures, protocols and a physical layer exploiting Long-Reach Passive Optical Network an integrated access and metro network interconnected with a low cost flat optical core network. Our architectural modelling results show that the benefits of node consolidation on the access side extends also to the core part, by enabling a flattening of the backbone network, bringing a substantial reduction in the number of router ports. In addition we report on testbed results demonstrating end-to-end service provisioning across multiple network layers, from application down to physical layer.

FiWiN5G invited presentations:

Vincent Chan
Cognitive all-optical fiber network architecture
V.W.S. Chan and E. Jang
Massachusetts Institute of Technology, Claude E. Shannon Communication and Network Group, Research Lab of Electronics, Cambridge, USA

The optical network of the future will have ~3 orders of magnitude increase in data rates, mostly due to large transactions. These elephant flows need fast scheduling of network resources and agile network adaptations for congestion control, load balancing and reconfiguration to cope with huge traffic transients and reconstitution for network resilience. This paper move beyond SDN as well as “orchestration,” to involve all layers particularly the optical Physical and Control layers for fast (~100 ms) and efficient adaptation using cognitive techniques.

Ivana Gasulla
Space-division multiplexing for fiber-wireless communications
I. Gasulla, S. Garcia, D. Barrera, J. Hervás, and S. Sales
ITEAM Research Institute, Universitat Politecnica de Valencia, Spain

We envision the application of optical Space-division Multiplexing (SDM) to the next generation fiber-wireless communications as a firm candidate to increase the end user capacity and provide adaptive radiofrequency-photonic interfaces. This approach relies on the concept of “fiber-distributed signal processing”, where the SDM fiber provides not only radio access distribution but also broadband microwave photonics signal processing. In particular, we present two different SDM fiber technologies: dispersion-engineered heterogeneous multicore fiber links and multi-cavity devices built upon the selective inscription of gratings in homogenous multicore fibers.

George Kalfas
Medium transparent MAC access schemes for seamless packetized fronthaul in mm-wave 5G picocellular networks
G. Kalfas1,2, J. Vardakas3, L. Alonso1, C. Verikoukis4, and N. Pleros2
1Dept. of Signal Theory and Communications, Technical University of Catalonia (UPC), Barcelona, Spain
2Department of Informatics, Aristotle University of Thessaloniki, Greece
3Iquadrat Informatica, Barcelona, Spain

4Telecommunications Technological Centre of Catalonia (CTTC), Castelldefels, Barcelona, Spain
Telecom operators are racing towards upgrading their facilities and broadband services in order to meet the highly challenging 5G operational framework in dense urban landscapes. The oversubscribed sub-6 GHz wireless band is lacking the necessary bandwidth to support the envisioned 5G data rates, suggesting the transition to mm-wave bands as the only viable scenario. In conjunction with the cell densification that is required to achieve the desired frequency reuse factor, it becomes obvious that the current CPRI-based fronthaul cannot cope with massive multi-Gbps traffic streams and a paradigm shift in resource allocation and network intelligence is necessary. To this end we propose a Medium Transparent MAC protocol specifically designated to operate over a converged mm-wave FiWi fronthaul infrastructure. Our approach allows for directly negotiating wavelength, frequency and time resources between the centralized unit and the mm-wave wireless terminals, while offering fast on-demand link formation following closely the demand fluctuation at the picocell level. In this paper we investigate the functional and physical consolidation as well as the respective performance of MT-MAC-enabled fronthaul and report on its application and suitability for mm-wave 5G access networks.

Paulo Monteiro
A worst case analysis of C-RAN fronthaul coverage length with Ethernet based technologies
A. de Sousa, D. Melo, and P. Monteiro
Instituto de Telecomunicações, Departamento de Eletrónica, Telecomunicações e Informática, Universidade de Aveiro, Portugal
The fronthaul between the Central Office, hosting the BBU pool, and the different located RRUs in a C-RAN has been based mainly on dedicated fibre links or, more recently, on dedicated lightpaths over a fibre network. A more cost effective solution is to deploy the C-RAN fronthaul based on Ethernet technologies but such solutions must be carefully investigated due to the very demanding latency and jitter requirements imposed by constant bitrate protocols, such as CPRI. In this paper, we conduct a worst case performance analysis to determine the maximum coverage length between the Central Office and each RRU imposed by CPRI, when the C-RAN fronthaul is based on EPON networks or based on switched Ethernet networks.

Paolo Monti
A flexible 5G RAN architecture with dynamic baseband split distribution and configurable optical transport
P. Monti1, Y. Li1,2, J. Mårtensson3, M. Fiorani4, B. Skubic4, Z. Ghebretensaé4, and L. Wosinska1
1KTH Royal Institute of Technology, Stockholm, Sweden
2Beijing University of Posts and Telecommunication, Beijing, China
3RISE Acreo, Kista, Sweden
4Ericsson Research, Stockholm, Sweden

This talk presents a new RAN concept referred to as Flexible RAN (F-RAN). In F-RAN, BPFs are strategically distributed within the RAN in order to optimize the trade-off between radio performance maximization and transport capacity requirement minimization. In the use case examined in this talk, tight radio coordination management schemes are used to manage radio interference. The F-RAN concept is applied to a radio network using a Dense Wavelength Division Multiplexing (DWDM) centric transport [M.R. Raza,  M. Fiorani,  A. Rostami,  P. Öhlen,  L. Wosinska,  P. Monti, "Demonstration of dynamic resource sharing benefits in an optical C-RAN," IEEE/OSA JOCN, vol. 8, no. 8, (2016)]. Two variants of F-RAN are proposed, i.e., Partially Centralized F-RAN (PCF-RAN), and Fully Distributed F-RAN (FDF-RAN). The performance evaluation of both PCF-RAN and FDF-RAN confirm that by applying the F-RAN concept it is possible to achieve a better utilization of transport resources compared to conventional C-RAN.

Chris Roeloffzen
Enhanced coverage though optical beamforming in fiber wireless networks
C. Roeloffzen1, P. van Dijk1, R. Oldenbeuving1, C. Taddei2, D. Geskus1, I. Dove1, R.B. Timens1, J. Epping1, A. Leinse1, and R. Heideman1
1LioniX International, Enschede, the Netherlands
2University of Twente, LPNO, MESA+ Research Institute for Nanotechnology, Enschede, the Netherlands
Integrated microwave photonics (IMWP) is a novel field in which the fast-paced progress in integrated, on-chip, optics is harnessed to provide breakthrough performances in well-established microwave photonic processing functions, which are traditionally realized using discrete optoelectronic components. A field where IMWP can have a strong impact is the one of Antenna Arrays for 5G networks. Such arrays offer a number of attractive characteristics, including a conformal array profile, electronic beamforming (beam shaping and beam steering), interference nulling and the capability to generate multiple antenna beams simultaneously. In many cases, however, the performance of a phased array is limited by the characteristics of the beamforming network (BFN) used. It is generally desired to realize beamformers with broad instantaneous bandwidth, continuous amplitude, and delay tunability while, at the same time, capable of feeding large arrays. This, however, is very challenging to achieve using only electronics. For this reason, in the last few years, an increasing amount of research has been directed to beamforming in the optical domain using, integrated microwave photonics solutions. Besides antenna array applications, opportunities for cost effective use of IMWP in switched delay lines has become feasible due to the continuous improvement of optical chips, particularly the achieved record-low propagation losses in Si3N4/SiO2-based-chips combined with the high integration density.

Andreas Stöhr
Field trial of a hybrid fiber wireless (HFW) bridge for 2.5 Gbit/s GPON
R. Chuenchom1, A. Banach2, Y. Leiba3, M. Lech2, N. Schrinski1, M. Yaghoubiannia1, A. Steffan4, J. Honecker4, and A. Stöhr1
1Universität Duisburg-Essen, ZHO/Optoelectronics, Duisburg, Germany
2Orange Polska, Orange Labs, Świdnik, Poland
3Siklu, Petach Tikva, Israel
4Finisar, Berlin, Germany

In this paper, we report on a field trial, demonstrating the seamless wireless extension of a real-world 2.5 Gbit/s Gigabit passive optical network (GPON) using a hybrid fiber wireless (HFW) bridge. Direct optic-to-RF conversion using a novel coherent photonic mixer (CPX) and direct RF-to-optic radio access units (RAU) were developed and employed to extend the reach of the GPON network using a 455 m long-distance 73.5 GHz millimeter-wave point-to-point (PTP) wireless link. The wireless GPON bridge was synchronized to the downlink transmission line rate of 2.5 Gbit/s. In the field trial, as total downlink traffic of about 2.5 Gbit/s was transmitted over SMF and the wireless bridge between the OLT and three ONU. The total uplink traffic from two ONUs to the OLT was about 1.2 Gbit/s.

Juan Vegas Olmos
Wireless communications surpassing fiber capacity: Micro- and millimeter-wave solutions up to D-band for 5G systems
J.J. Vegas Olmos1 and I.T. Monroy2
1Mellanox Technologies, Roskilde, Denmark
2Technische Universiteit Eindhoven, the Netherlands

In this paper, we present the latest experimental work on millimetre-wave links operating at fiber-like capacity regimes: from UWB communications supporting up to 35 Gbit/s to D-band communications operating at 352 Gbit/s. We provide insights on these technologies and hints on next steps to achieve 1 Tbit/s in the air.

Christos Verikoukis
Towards high capacity and low latency backhauling in 5G: The 5G STEP-FWD vision
J.S. Vardakas1, I.T. Monroy2, L. Wosinska3, G. Agapiou4, R. Brenot5, N. Pleros6, and C. Verikoukis7
1Iquadrat Informatica S. L., Barcelona, Spain
2Institute for Photonics Integration, Eindhoven University of Technology, Eindhoven, the Netherlands
3Dept. of Information and Communication Technology, Royal Institute of Technology KTH, Stockholm, Sweden
4Hellenic Telecommunications Organization S.A.-OTE, Athens, Greece
5III-V Lab, Route de Nozay, Marcoussis, France
6Dept. of Informatics, Aristotle University of Thessaloniki, Thessaloniki, Greece
7Telecommunications Technological Centre of Catalonia (CTTC/CERCA), Barcelona, Spain

This paper presents the vision of the 5G STEP-FWD project, which is funded by the European Commission, and targets to provide a novel optical-wireless networking solution for the provision of high speed connectivity to end users. The features of the new architecture, based on the utilization of Ultra-Dense Wavelength Division Multiplexing Passive Optical Networks as the backhaul network, providing access to hyper dense mmWave networks, are presented in detail. Moreover, this article presents the research challenges and how they are addressed in 5G STEP-FWD in order to achieve the spectral, delay, and energy efficiency requirements of 5G.

Flex-ON invited presentations:

Alex Alvarado
Designing adaptive coded modulation for optical networks via achievable information rates
A. Alvarado1, D. Ives2, and S. Savory2
1Eindhoven University of Technology, the Netherlands
2University of Cambridge, UK

Achievable information rates are discussed as a tool to analyse and design optical networks. It is shown that the maximum throughput of the network and its dependency of different network parameters can be predicted with such a tool.

João Pedro
Raman amplification: Key enabler for next-generation flexible optical networks?

J. Pedro1,2, N. Costa1, and M. Gunkel3
Coriant Portugal,  Amadora, Portugal
Instituto de Telecomunicações, Instituto Superior Técnico, Lisboa, Portugal

Deutsche Telekom, Fixed Mobile Engineering, Darmstadt, Germany

The ever-increasing demand for capacity in optical networks is driving the development of transponders capable of achieving spectral efficiencies of up to 8 bit/s/Hz using advanced modulation formats and coherent-detection. However, operating at the highest spectral efficiency is accomplished at the expense of shorter transparent reach, potentially requiring the deployment of additional expensive optical signal regenerators (3Rs). This limitation can be mitigated to a certain extent by exploiting enhanced optical amplification strategies, such as Raman amplification. Interestingly, the prevalent paradigm of only using Raman amplification in the longer fibre spans of long-haul networks may be on the verge of being challenged. This paper provides insight on the potential of Raman amplification in next-generation flexible optical networks by showing the network-level benefit provided by Raman amplification when transmitting a wide assortment of channel formats in meshed optical networks.

Li Yan
Capacity scaling of flexible optical networks with nonlinear impairment
Li Yan and E. Agrell
Chalmers University of Technology, Goteborg, Sweden

Efficient resource utilization with a satisfying quality of service is the key to high capacity in flexible optical networks. In our work, this is achieved by accompanying the resource allocation with the Gaussian noise model, which estimates the nonlinear physical-layer impairments. The study includes variable launch power, modulation formats, error-correcting code rates, and various new network features to provision traffic requests efficiently. The advantageous performance of the flexible optical networks is demonstrated by simulation results as well as theoretical analysis.

GOC invited presentations:

Dieter Bimberg
How can we accommodate the rapidly increasing power consumption of the Internet? “Green” optical interconnects based on novel VCSELs!
G. Larisch1 and D. Bimberg1,2
1Institut für Festkörperphysik, Zentrum für Nanophotonik, Technische Universität Berlin, Germany
2 King-Abdul-Aziz University, Jeddah, Saudi Arabia

The rapidly growing demand for higher data rates in optical access networks, backplanes, memories, on-chip CPU, and chip-to-chip optical interconnects requires novel ultra-high bit rate sources, which are more energy efficient per bit than anything presently existing.  A low-cost method to adjust the mirror reflectivity of vertical-cavity surface-emitting lasers (VCSELs) helps to optimize their cavity photon lifetime. The joint variation of photon lifetime and the oxide aperture diameter of our 980 nm VCSELs allows optimization procedures between the laser parameters. A new indicator helps to judge the optimum mirror reflectivity to enable increased bit rates in concert with reduced energy consumption, as well as temperature stability, and a smaller bias current density. Error-free back-to-back data transmission at 50 Gbit/s over a wide temperature range from 25°C to 75°C for completely unchanged driving conditions is presented amongst other progress, including a 400 fJ/bit data transmission energy efficiency at 50 Gbit/s.

Taisir El-Gorashi
On the energy efficiency of MapReduce shuffling operations in data centers
S.H. Mohamed, T.E.H. El-Gorashi, and J.M.H. Elmirghani
School of Electronic and Electrical Engineering, University of Leeds, UK

This paper aims to quantitatively measure the impact of different data centers networking topologies on the performance and energy efficiency of shuffling operations in MapReduce. Mixed Integer Linear Programming (MILP) models are utilized to optimize the shuffling in several data center topologies with electronic, hybrid, and all-optical switching while maximizing the throughput and reducing the power consumption. The results indicate that the networking topology has a significant impact on the performance of MapReduce. They also indicate that with comparable performance, optical-based data centers can achieve an average of 54% reduction in the energy consumption when compared to electronic switching data centers.

Leonid Kazovsky
Small networks, large energy: New frontiers in green IT
L. Kazovsky1, A.P. Gowda1, and J. Prat2
1Photonics and Networking Research Lab sp., Stanford University, USA
2Universitat Politècnica de Catalunya, Barcelona, Spain
World IT infrastructure is growing rapidly both in terms of bit rates and in terms of the number of links and nodes.  As a result, its energy footprint is rapidly growing just as rapidly both in absolute numbers and as a fraction of the overall world energy consumption.  Furthermore, the energy consumptions of individual nodes is beginning to impose significant design challenges and limitations. These trends are not sustainable and point to a new frontier in IT design: How to decrease its energy consumption while simultaneously improving its performance?  Much of the effort until now has been focused on large networks (such as intercontinental and cross-continental networks) and large nodes (such as large data centers serving governments and large corporations). However, our research shows that small networks - i.e., intra-building and access networks - consume more energy than large networks.  While this conclusion may seem counterintuitive, it stems directly from the sheer number of small networks that is much larger than that of large networks. Therefore, the energy needs of small networks must be reduced if the overall energy consumption of global networks is to be addressed. This talk will examine two types of small networks: Intra-building networks and access networks.  We discuss their architecture, technology, major energy sinks and overall energy consumption.  Further, we examine possible applications of analog ROF, digital ROF and coherent detection in small networks and attempt to predict if these technologies can reduce their energy consumption vs incumbent technologies.

Leo Spiekman
Low power SOAs
L.H. Spiekman, Aeon Corp., Princeton, US
We will discuss some strategies for reduced power consumption of semiconductor optical amplifiers.  This is important for commercial applications where the SOA needs to be incorporated into a compact low-power module such as for datacenter communications.

Cédric Ware
Towards WDM slot switching for aggregation access and metropolitan applications: The ANR N-GREEN project
C. Ware1 and D. Chiaroni2
1LTCI, Télécom ParisTech, Université Paris-Saclay, France
2Nokia Bell Labs, Nozay, France

WDM has been generally proposed to groom wavelengths for transport applications. This paper will describe our attempt to reduce cost and energy consumption of smart network elements, through an extended use of WDM techniques at the data link level. This paper will draw the advantages of this approach and will demonstrate that this new direction is efficient to keep the frequency processing at a reasonable value in the electronic interfaces, to validate optical bypasses concepts even for long haul applications, to reduce the complexity of ROADM systems and to increase the energy efficiency, through a better exploitation of an integrated optical technology and of the efficient use of the available optical bandwidth. This paper demonstrates that by combining components realized for the data com, or for the NGPON2 systems and a parallelism in the optical domain, it is then possible to decrease dramatically the cost of the systems while offering better performance than classical Ethernet technologies.

GOWN invited presentations:

Cicek Cavdar
Cloud RAN with optical and mm-wave transport technologies
Huajun Wang, A. Hossain, and C. Cavdar
KTH, Stockholm, Sweden

Cloud RAN has been regarded as a future solution for 5G mobile network architecture in terms of combination of implementing the very tight radio coordination schemes and sharing baseband processing and cooling system resources. However, the stringent delay and high capacity requirement for the fronthaul, the segment of the network between the centralized Baseband Units(BBU) and distributed Remote Radio Heads(RRH), shown to be one of the biggest barriers to larger deployments. Different options are possible for Cloud RAN transport technologies such as optical access technologies or radio technologies utilizing mm-Wave frequency bands. Stringent delay constraint can be alleviated by splitting the BBU processing functions into different layers and keeping the lower layer functions close to the RRH. In this paper,  given the number of radio sites, we present and compare different transport technology options to support Cloud RAN: E-PON, TWDM-PON and mm-Wave under different function splits. We calculate the transport capacity requirement for four baseband splitting solutions and adopt three different transport technologies to support Cloud RAN. The end-to-end power consumption is calculated by adding up the power utilized by RRHs, fronthaul network and baseband processing. The results show that hybrid TWDM-PON mm-Wave transport technology can be promising for dense radio deployments with a certain function split.

Ivan Djordjevic
RF-assisted coherent detection based continuous variable (CV) QKD with high secure key rates over atmospheric turbulence channels
Zhen Qu and I.B. Djordjevic
Department of Electrical and Computer Engineering, University of Arizona, Tucson, USA

In this invited paper, a high-speed continuous-variable quantum key distribution (CV-QKD) system is investigated in the presence of atmospheric turbulence, which is enabled by employing the wavelength, polarization, and orbital angular momentum (OAM) states as degrees of freedom. Four-state discrete modulation is used for the key shaping for the convenience of easy generation, as well as to enhance the reconciliation efficiency. The polarization insensitive atmospheric turbulence channel is emulated by two spatial light modulators (SLMs) on which randomly generated azimuthal phase patterns yielding Andrews’ spectrum are recorded. The phase noise is mitigated by the phase noise cancellation (PNC) stage, and transmittance fluctuation is monitored directly by the D.C. component in the PNC stage. After system calibration, a total secret key rate (SKR) of 240 Mb/s can be reached in the presence of atmospheric turbulence.

Roberto Gaudino
Alternative solutions for fronthauling based on DSP-assisted radio-over-fiber
P. Torres-Ferrera1, S. Straullu2, S. Abrate2, and R. Gaudino3
1Institute of Engineering, Universidad Nacional Autónoma de México, Mexico
2ISMB, Istituto Superiore Mario Boella, Torino, Italy
3Politecnico di Torino, Italy

We review alternative solutions for optical fronthauling in next generation fixed-mobile converged architectures that try to solve the problems related to the extremely high bit rates required by current fronthauling implementations based on the so-called digitized Radio over Fiber (as for the CPRI or OBSAI standards). In particular, we present our most recent results on Digital Signal Processing (DSP) assisted Frequency Division Multiplexed (FDM) aggregated radio over fiber solutions. We experimentally show two DSP-based optimization at the transmitter and/or receiver that improves the received Error Vector Magnitude (EVM). Moreover, we discuss on simple spectral estimation of the EVM parameter at the Remote Radio Head (RRH).

Christina Lim
Transport schemes for fiber-based fronthaul for transporting 60 GHz wireless signals
C. Lim, Yu Tian, Ka-Lun Lee, and A. Nirmalathas
Department of Electrical and Electronic Engineering, Melbourne School of Engineering, The University of Melbourne, Australia

In this paper, we review our recent work in the area of 60 GHz radio-over-fiber fronthaul links. We compared the different transport schemes incorporating modified double-sideband suppressed carrier (DSB-SC) and optical single sideband with carrier (OSSB) modulation formats to cater for the transport of 60 GHz wireless signals. Our results show that OSSB links exhibits better receiver sensitivity however with trade-offs of requiring larger bandwidth modulators and higher frequency local oscillator.

Carmo Medeiros
Wireless-optical transceiver architectures for 60 GHz LANs
M.C.R. Medeiros1, P. Almeida1, B.M. Oliveira1, P. Laurêncio1,2, and P.M. Monteiro3
1IT-Instituto de Telecomunicações, Departamento de Engenharia Eletrotécnica e de Computadores, Universidade de Coimbra, Portugal
2University of Algarve, Faro, Portugal
3IT-Instituto de Telecomunicações, Departamento de Eletrónica, Telecomunicações e Informática, Universidade de Aveiro, Portugal

The availability of low cost commercially available components operating at 60 GHz, mainly driven by the approval of the consumer oriented IEEE 802.11ad and 802.15.3c standards, is expected to boost the deployment of 60 GHz wireless networks where an unlicensed band with around 7 GHz bandwidth is available. Nevertheless, the transmission of 60 GHz wireless signals is limited to a few meters (~10 m), which implies the deployment of multiple radio access points to cover a single house or building. Radio over fiber (RoF) technology can be an effective solution for delivering 60 GHz broadband signals, however the implementation of this scenario requires flexible low cost wireless-optical transceivers. The objective of this paper is to discuss and compare several wireless-optical transceiver architectures identifying their major advantages and limitations.

Mehdi Shadaram
Effect of different optical codes on a W-band WDM-over-OCDMA system
M.K Eghbal1, F. Aminian2, and M. Shadaram1
1Department of Electrical and Computer Engineering, University of Texas at San Antonio, USA
2Department of Engineering Science, Trinity University, San Antonio, Texas. USA

The dramatic increase in demand for services that require high bandwidth and augmented bitrate to function properly has become a trend in recent years. In order to comply with the current demand, telecom companies struggle to enlarge the offered capacity as well as to minimize the latency and to enhance the reliability of the network. An effective technique to increase the capacity is to move to higher frequency bands, such as millimeter wave band, where the inherent features promise larger capacities and less interference. The other proven method to increase the capacity is to incorporate optical coding in conjunction with the guidelines of optical code division multiple access (OCDMA) where the number of users is increased based on the assignment of optical orthogonal codes to every user. Finally, through the application of multiple wavelengths to transmit optical encoded signals in multiple channels, as suggested by the wavelength division multiplexing (WDM) scheme, the capacity can be increased substantially.  In this paper, a W-band WDM-over-OCDMA system is presented. The simulation results show the effect of various optical codes, profiled in a superstructure fiber Bragg grating (SSFBG) device as encoder/decoder, and wavelength channels on the BER versus the received optical power.

Masatoshi Suzuki
Optical and wireless integrated technologies for future mobile networks
M. Suzuki, S. Ishimura, K. Tanaka, and K. Nishimura
KDDI R&D Laboratories, Japan

The traffic in optical and mobile networks has been rapidly increasing. The peak rate of 5G mobile networks will be comparable to that of FTTH.  In this paper, we will discuss integrated optical and wireless technologies for efficient use of bandwidth of future mobile back/front-haul networks.

Gemma Vall-llosera
Photonics for radio access networks
G. Vall-Llosera, Wei-Ping Huang, E. Westerberg, and S. Albrecht
Ericsson AB, Stockholm, Sweden

In this work we analyse radio access networks (RAN) deployments from the capacity and cost points of view. We find that in order to support the new radio (NR) with system bandwidth of 800MHz and reduce the number of fibre connections between NR and baseband units (BBU) one can use dense wavelength division multiplexing (DWDM), pulse amplitude modulation (PAM4) or multicore fibre. We also find that spectrum and site are the most costly factors in a wide-area RAN deployment and we propose optical solutions to cope with this cost: a) advanced antenna solutions to improve uplink and downlink and downlink performance (throughput and coverage) by means of optical beamforming with silicon photonics phase shifters, or microstructural optical fibres; b) reducing footprint by means of silicon photonics; c) increasing capacity per site exploiting ultra-dense WDM transceivers, PAM4 transceivers, multicore fibre.

Carmen Vázquez Garcia
Monitoring systems and remote powering for next generation broadband access networks
C. Vázquez, D.S. Montero, J.D. López-Cardona, A. Tapetado, J. Montalvo, P. Contreras, and P.J. Pinzón
Carlos III University, Madrid, Spain

Future high capacity of the 5G radio environment will boost transport networks to be adapted. The high bandwidth, together with stringent delay and jitter requirements, make dedicated optical connectivity a preferred solution for fronthaul. Those Radio Access Networks (RAN) apart from higher capacity and lower latency should have higher energy efficiency. Reliability becomes also critical as each Remote Radio Head (RRH) may connect several mobile users. Therefore, preventive and in-service remote fiber monitoring solutions are needed in order to timely detect and locate faults to shorten the service downtime. Meanwhile power over fiber can provide flexibility to those solutions while improving costs in those cases where RRH should be deployed in places lacking external power supply in order to fulfil the desired coverage. Different monitoring and remote powering techniques will be presented.

Xianbin Yu
Beyond 100 Gbit/s wireless connectivity enabled by THz photonics
Xianbin Yu1, Shi Jia1, Xiaodan Pang2, T. Morioka3, L.K. Oxenloewe3
1College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, China
2School of ICT, KTH Royal Institute of Technology, Kista, Sweden
3DTU Fotonik, Technical University of Denmark, Lyngby, Denmark

Beyond 100 Gbit/s wireless connectivity is appreciated in many scenarios, such as big data wireless cloud, ultrafast wireless download, large volume data transfer, etc. In this talk, we will present our recent achievements on beyond 100 Gbit/s ultrafast THz wireless links enabled by THz photonics technology. We will also discuss technical challenges of driving the system even faster.

LFSR invited presentations:

Vasily Astratov
Spotlight on microspherical nanoscopy: Experimental quantification of super-resolution
V.N. Astratov1, A. Brettin1, F. Abolmaali1, C. McGinnis1, K.F. Blanchette1, Y.E. Nesmelov1, A.V. Maslov2, N.I. Limberopoulos3, D.E. Walker Jr.3, and A.M. Urbas4
1University of North Carolina at Charlotte, USA
2 University of Nizhny Novgorod, Nizhny Novgorod, Russia
3Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, USA
4Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, USA

A classification of label-free super-resolution imaging mechanisms is given based on the nonlinear reduction of the point-spread function (PSF), near-field scanning, image magnification and gain, structured and sparse illumination, and information approaches. We argue that the super-resolution capability of contact microspheres stems from an image magnification effect taking place in close proximity to the object with the contributions of its optical near-fields. It is shown that experimental quantification of resolution in a label-free microscopy requires convolution with 2-D PSF. We propose a combination of microspherical nanoscopy with nanoplasmonic illumination for imaging biomedical samples. We applied these techniques for imaging of polystyrene nanospheres, actin protein filaments, as well as yeast cells and observed a clear resolution advantage over standard microscopy techniques.

Geoffroy Lerosey
Subwavelength focusing and imaging from the far field using time reversal in subwavelength scaled resonant media
F. Lemoult, M. Dupré, M. Fink, and G. Lerosey
Institut Langevin, ESPCI ParisTech and CNRS, Paris, France

In this talk we will show how the use of time dependent and broadband wave fields, in conjunction with media structured at the subwavelength scale and supporting resonant eigenmodes, permits to beat the diffraction limit from the far field for imaging or focusing purposes. Examples will be given in the microwave, the acoustic, and the optical domain.

Femius Koenderink
Resolving nano-antenna physics through amplitude, polarization and phase of far field angular distributions of light
A.F. Koenderink, AMOLF, Amsterdam, the Netherlands
The radiation pattern of a single nano-object completely encodes its multipole decomposition in amplitude, polarization, and phase.  In this sense you could argue that a complete measurement of far-field information allows full resolution of the physics of a nano-object,  even though converting a multipole  decomposition to a near-field will require additional information on an objects size and shape.  Recently we demonstrated high-NA full Stokes-polarimetry, thereby resolving amplitude and polarization vector for each emission angle collected in single nano-object scatterometry, single nano-antenna fluorescence, and angle-resolved cathodoluminescence (CL). Currently we develop phase-resolved  optical Fourier microscopy, i.e., phase-resolved mapping of single object radiation patterns. I present digital off-axis holography as a method to measure phase distributions in radiation patterns benchmarked on plasmonic bulls’eye and spiral antennas.

Alexey Maslov
Theoretical resolution of contact microspherical nanoscopy
A.V. Maslov1 and V.N. Astratov2
1University of Nizhny Novgorod, Russia
2University of North Carolina at Charlotte, USA

The mechanisms of super-resolution imaging by contact microspherical (or microcylindrical) nanoscopy remain an enigmatic question since these lenses neither have an ability to amplify the near-fields like in the case of far-field superlens, nor they have a hyperbolic dispersion similar to hyperlenses. In this work we study theoretically and numerically the resolution of point dipoles which are imaged through microcylinders and microspheres. Out approach is based on rigorous solution of the Maxwell equations for the dipole emission near microstructures. This allows us to account for various physical effects that may differentiate the regime of microsphere-based imaging from the standard microscopy. These effects include the near-field coupling to microspheres, excitation of microsphere resonances (whispering gallery modes), coherence and polarization of dipole emission. Their role in resolution will be discussed.

Evgenii Narimanov
Hyper-structured illumination: Label-free super-resolution imaging with hyperbolic metamaterials
E. Narimanov, School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, USA
In this paper, we present a new approach to super-resolution optical imaging, based on structured illumination in hyperbolic media. Hyperbolic materials, either natural crystals or artificial composites with the opposite signs of the dielectric permittivity components in two orthogonal direction, support propagating waves with the wavenumbers unlimited by the frequency, and therefore allow the generation of subwavelength illumination patterns – which dramatically improving the imaging resolution. The proposed system has planar geometry, offers unlimited field of view, and is robust with respect to optical noise and material losses.

Omer Wagner
Label free microscopy with enhanced localization performance based upon temporally modulated polarization
O. Wagner1, M. Schultz2, A. Meiri1, E. Edri2, R. Meir1, H. Shpaisman3, E. Sloutskin2, and Z. Zalevsky1
1Faculty of Engineering and the Nanotechnology Center, Bar-Ilan University, Ramat-Gan, Israel
2Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
3Department of Chemistry, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel

Recent microscopy techniques use nanoparticles as contrast agents that assist in realizing super resolved imaging of the inspected sample. While the sample itself is not labelled, its optical properties and form are revealed from the agent's location and movement. Gold nanoparticles are frequently used for compound cellular imaging due to their plasmonic resonance that occurs in the visible regime. While the effect dramatically enhances their absorbance active area, additional enhancement techniques are still needed in order to reach adequate signal to noise levels and differentiate between adjacent nanoparticles.  In this paper we demonstrate an effective way to image a sample using specialized eccentric gold nanoparticles while exploiting the polarization dependency of their plasmonic resonance. Temporal modulation of the illumination polarity causes appropriate temporal flickering of the nanoparticles. The method enhances localization by eliminating noise that differs in frequency from the temporal modulation. Differentiation between nanoparticles is concurrently gained as the flickering is changed in relation with the angle between their eccentric axis and the polarization angle.

MARS invited presentations:

Germán Arévalo
A techno-economic network planning tool for PON deployment including protection strategies
G.V. Arévalo1 and R. Gaudino2
1Department of Electronical Engineering, Universidad Politécnica Salesiana, Quito, Ecuador
2Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Italy

We developed a techno-economic network planning tool for deployment of PON networks in large cities involving hundreds of thousands of end-users. The tool use techno-economic data and street-aware algorithms to estimate the global cost of the network. In the present new work, we extend the application scenario of our planning tool to estimate the increase of cost when different types of protection strategies are introduced in PON networks.

Ignacio de Miguel
Techno-economic comparison of dynamic traffic grooming strategies for elastic optical networks
S. Fernández, I. de Miguel, R.J. Durán, J.J. Castro, N. Merayo, J.C. Aguado, L. Ruiz, P. Fernández, R.M. Lorenzo, and E.J. Abril
E.T.S.I. de Telecomunicación, Campus Miguel Delibes, Universidad de Valladolid, Spain

We extend past work presented at ICTON 2015, where we reviewed and extended a number of dynamic traffic grooming algorithms proposed by Zhang et al. for elastic optical networks. In that paper we showed that, on the one hand, different grooming policies lead to different connection blocking ratios and have different associated economic costs. On the other hand, different types of transceivers (supporting a single type of modulation format, or being able to generate different ones) also lead to different results in terms of those parameters: blocking ratio and cost. So, a question arises: what is the best option when designing an elastic optical network? Is it better to use a cost-effective grooming policy with transceivers supporting several modulations, or to use cheaper fixed-modulation transceivers combined with an effective policy in terms of blocking ratio? In this paper, we analyze which combination of transceiver type and grooming policy has advantages from a techno-economic perspective (considering both CAPEX and OPEX), while providing a target performance in terms of blocking ratio.

Barry O'Sullivan
Generation of a reference network for Ireland and its contribution to the design of an optical network architecture
A. Arbelaez, D. Mehta, B. O'Sullivan, L. Quesada, and A. Sasmaz
Insight Centre for Data Analytics, University College Cork, Ireland

Realistic reference networks are critical for all techno-economic evaluations. As this information was not publicly available for Ireland, we generated such a reference network. In this paper we elaborate on the challenges faced during the generation and present some statistics. We also show how this is used in the design of an optical architecture for the same country. The level of detail of the reference network needed varies according to the layer of the architecture that is being designed. In this paper we show how the original reference network is reduced while maintaining important properties for the design of the architecture. We also elicit geotypes from the structure of the reference network and discus the importance of this computation in the design of the optical distribution network.

Ken-ichi Sato
Role of grouped routing in creating cost effective and bandwidth abundant networks
Ken-ichi Sato, Nagoya University, Japan
The continued increase in Internet traffic, particularly in metro networks, is spurring wide deployment of optical networking technologies for wavelength routing. In metro networks, the number of nodes traversed can be very large and hence the optical filtering penalty incurred in the ROADM/OXC nodes can be critical as it degrades fiber frequency utilization. This presentation elucidates how grouped routing, hierarchical optical paths, grouped routing entity pipes, and virtual direct routing, is effective.

Massimo Tornatore
C-RAN baseband pooling: Cost model and multiplexing gain analysis
M. Shehata1, A. Elbanna2, F. Musumeci1, and M. Tornatore1
1Department of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
2Faculty of Electrical Engineering and Information Technology, Technische Universität Chemnitz, Germany
Centralized Radio Access Network (C-RAN) is a promising mobile network architecture to face the increasing mobile traffic demand. In this paper, we propose a detailed model to evaluate the statistical multiplexing gain achieved through C-RAN baseband pooling, and based on this model we can perform a cost analysis taking into consideration different geographical type areas (geotypes). We show the influence of pool dimension (number of aggregated sites per pool), user distribution, users and sites densities on the multiplexing gain and on the network cost.

Mateusz Żotkiewicz
On cost of the uniformity in FTTH network design
M. Żotkiewicz and M. Mycek
Warsaw University of Technology, Poland

The research aims in estimating the impact of various levels of administratively imposed structural regularities and equipment uniformities on FTTH network designs. We enhance our FTTH network optimization platform with algorithms that allow imposing additional constraints on the returned solutions. We use the platform to compare, in terms of CAPEX, obtained FTTH network designs. Additionally, we use available methods to minimize CAPEX generated during network deployment, which is only possible when adequate levels of flexibility of designs are held.  The research is intended to show advantages and drawbacks related to imposing administrative constraints on flexibility of FTTH network designs.

MWP invited presentations:

Mario Armenise
New microwave photonic filter based on a ring resonator including a photonic crystal structure
C. Ciminelli, F. Dell’Olio, G. Brunetti, D. Conteduca, and M.N. Armenise
Optoelectronics Laboratory, Politecnico di Bari, Italy
Microwave photonic filters with a performance not achievable by the conventional RF technology, are currently a hot topic in the field of microwave photonics. In this paper, after a brief review of the state-of-the-art of microwave integrated photonic filters and their application in space engineering, the design of a new band-pass filter configuration based on a ring resonator with a photonic crystal included in the resonant path is proposed. The achieved performance parameters are a full-width-at-half-maximum of 10 pm, a Q-factor of 1.5×105, with an extinction ratio equal to 40 dB, and a maximum ripple less than 0.5 dB, within the wavelength range λ0 ± FWHM/4 (with λ0 = 1550 nm). The ring is in silicon technology and it can be integrated with other optoelectronic/photonic components of the filter through a hybrid approach.

Hercules Avramopoulos
Enabling photonic integration technology for microwave photonics in 5G systems
C. Tsokos1, P. Groumas1,2, V. Katopodis1, H. Avramopoulos1, and C. Kouloumentas1,2
1National Technical University of Athens, Athens, Greece
2Optagon Photonics, Athens, Greece

Within the European project HAMLET, we develop a large scale photonic integrated circuit as a flexible interface between the optical front-haul part and the wireless access part at the remote antenna units (RAU) of future 5G networks. The circuit will be based on the hybrid integration of a polymer platform (PolyBoard) with a low-loss silicon-nitride platform (TriPleX), and will accommodate a number of processing functionalities in the digital and analog domains including optical beamforming. The analog optical link on-chip will be based on the use of graphene-based electro-absorption modulators in the polymer part of the circuit and will be able to transfer through the optical beamforming network radio signals at 28 GHz with 1 Gbaud symbol rate and modulation format up to 64-QAM. In this paper, we present early experimental results with bulk components that emulate the operation and evaluate the expected performance of our optical system on-chip.

José Capmany
Compact programmable RF-photonic filters using integrated waveguide mesh processors
D. Pérez1, I. Gasulla1, L. Crudgington2, D.J. Thomson2, A.Z. Khokhar2, Ke Li2, Wei Cao2, G.Z. Mashanovich2, and J. Capmany1
1Photonics Research Labs, ITEAM, Universitat Politècnica de València, Spain
2Optoelectronics Research Centre, University of Southampton, UK

Integrated waveguide meshes have been recently proposed as an advanced technical solution for the implementation of universal processors. In this paper we investigate their potential for the implementation of simple and cascaded programmable RF-photonic filters. We specifically address the case of single sideband and carrier injection filters and the possibility of implementing parallel filtering schemes. We demonstrate an extensive amount of device flexibility including: circuit design topology, filter tunability and reconfigurability. The device composed of 7-cells allows the synthesis of basic photonic circuits and more complex cascaded combinations of ring resonators and Mach-Zehnder interferometers.

Marco Grande
Engineered graphene for optically transparent microwave devices
M. Grande1, G.V. Bianco2, M.A. Vincenti3, D. de Ceglia3, P. Capezzuto2, V. Petruzzelli1, M. Scalora4, G. Bruno2, and A. D’Orazio1
1Dipartimento di Ingegneria Elettrica e dell’Informazione, Politecnico di Bari, Italy
2Istituto di Nanotecnologia – CNR-NANOTEC, Bari, Italy
3National Research Council, Charles M. Bowden Research Center, RDECOM, Redstone Arsenal, Alabama, USA
4Charles M. Bowden Research Center, RDECOM, Redstone Arsenal, Alabama, USA

Most of microwave devices are not optically transparent in the visible range. Optically transparent microwave devices, such as absorbers, filters and antennas, would be desirable since they could be fully exploited for shielding systems, military applications or integrated in window glasses and along with photovoltaics. These devices could also play a key role in micro- and nano- satellite applications where the maximization of the surface area for the solar power collection remains a critical issue. In this paper, we will review configurations of graphene-based microwave devices that attempt to be optically transparent. In this framework, we will also propose our latest results on the realization of microwave absorbers fully transparent in the optical regime [M. Grande et al., Scientific Reports, 5 (2015) 17083], [M. Grande et al., Optics Express, 24 (2016) 22788-22795]. These devices are based on the Salisbury screen configuration, which consists of a lossless spacer (glass) sandwiched between two graphene sheets whose sheet resistances are different and properly engineered. Theoretical results corroborate experimental ones revealing the possibility to achieve near-perfect electromagnetic absorption in the microwave X-band.

Wojciech Knap
THz imaging and wireless communication using nanotransitor based detectors: From basic physics to first real world applications
W. Knap1, N. Dyakonova1, G. Cywinski2, D. Coquillat1, K. Szkudlarek2, I. Yahniuk2, C. Archier3, B. Moulin3, M. Triki3, M.M. Hella4, V. Nodjiadjim4, A. Konczykowska4, and M. Sypek5
1Charles Coulomb Laboratory, Montpellier University & CNRS, France
2Optical Information Processing Laboratory, Warsaw University of Technology, Poland
3T-Waves Technologies ( TWT) Montpellier, France
4III-V Lab, Joint Lab, Bell Labs, Thales Research and Technology and CEA-LETI, France
5High Pressure Institute Polish Academy of Sciences Warsaw, Poland
An overview of main results concerning THz detection by nanometer field effect transistors ( FETs) and Heterojunction based transistors (HBTs) is presented. In particular the physical limits of the responsivity, speed and the dynamic range of these detectors are discussed. We present also applications of these detectors for THz wireless communication in C-MOS technology and construction of focal plane arrays.  We show , how these arrays, together with in purpose developed diffractive 3D printed optics lead to construction of the demonstrators of safety and industrial quality control scanners.

Robert Minasian
Stimulated Brillouin scattering based microwave photonic signal processors
R. Minasian and Xiaoke Yi
University of Sydney, Australia

Photonic signal processing, using photonic approaches to condition microwave signals, is attractive due to its intrinsic advantages of high time-bandwidth product and immunity to electromagnetic interference (EMI). The use of stimulated Brillouin scattering (SBS) is particularly attractive for obtaining precise processing of selected spectral sidebands to realize high-resolution microwave photonic signal processors, because of the inherent narrowband nature of SBS. Recent new methods that can realize SBS based signal processors are described. This includes a microwave photonic instantaneous frequency measurement system that can simultaneously measure multiple-frequency signals while achieving very high resolution and wide frequency measurement range. It is based on the frequency-to-time mapping technique implemented using a frequency shifting recirculating delay line loop and a narrow-band optical filter realised by the in-fibre SBS effect. Experimental results demonstrate a multiple-frequency measurement capability over a frequency range of 0.1 – 20 GHz that can be extended to 90 GHz, and with a measurement resolution of 250 MHz. Also techniques for realizing optical frequency shifters that can shift the light frequency in the microwave or millimetre-wave frequency range are described. This all-optical approach, based on an SBS technique, is capable of operating over a wide frequency range and with tunable capabilities. Experimental results show optical frequency shifts from 2 to 20 GHz and demonstrate a widely tunable frequency shifting operation. The characteristics of a high-resolution filter based on SBS within a fibre has also been obtained, using a new optical vector network analyser technique based on an optical single sideband technique using an integrated silicon photonics dual-microring resonator. Measurements have shown the ability to obtain high-resolution spectral characteristics of the effect of optical pump power on the amplitude and phase response of the ultra-narrowband Brillouin filter.

José Mora
Analysis of key parameters in MWP-LCI systems
J. Benítez, M. Bolea, and J. Mora
OQCG, ITEAM Research Institute, Universitat Politecnica de Valencia, Spain

Low coherence interferometry (LCI) is a well-known measurement technique able to provide an axial precision in the order of the microns. Its application to a wide variety of fields like medicine has attracted the interest of many authors mainly due to its non-invasive characteristic. By combining LCI and microwave photonics (MWP), we take profit from the inherent stability that the RF domain offers to improve the general performance of key parameters. In this paper, an analysis of key parameters in a MWP-LCI structure is carried out. The main target is to demonstrate the feasibility of a LCI system by means of MWP technology featuring unique properties beyond the current state of the art. The analyzed scheme is able to obtain the optical path difference (OPD) related to a sample by retrieving the low-coherence interferogram in the RF domain. Moreover, we provide an accurate definition of resolution for MWP-LCI based system, which is closely related to the shape of the optical source profile employed. Finally, experimental demonstration of the analysis carried out in this work is also attached.

Salvador Sales
Multiplexing FBG sensors combining microwave photonics and phase modulation
J. Hervás, J. Madrigal, D. Barrera, and S. Sales
iTEAM Research Institute, Universitat Politècnica de València, Spain

We apply phase modulation techniques at different wavelengths to generate microwave tones that allows us to interrogate multiplexed sensors. The interrogation technique has a resolution far below 1 pm with a simple system and no need of post-processing This approach relies on basic concepts of microwave photonics technique operating under low coherence regime A remarkable linear sensitivity of 1 dB/pm for a movement up to 10 pm of the Bragg wavelength is demonstrated through experimental measurements.

NAON invited presentations:

Srinivasan Anand
Optical coatings and films based on photonic semiconductor nanostructure assemblies
S. Anand1, Y. Désières1,2, D. Visser1, and D-Y. Chen1
1KTH Royal Institute of Technology, Department of Applied Physics, Kista, Sweden
2CEA-LETI MINATEC, Grenoble, France

Photonic semiconductor nanostructure assemblies offer unique possibilities for light manipulation as well as for tailoring light-matter interaction by appropriate choice of their geometrical and material properties. The material-structure combination offers a variety of options for wavelength specific applications, deriving from the electronic properties of semiconductors and optical properties of individual and assemblies of nanostructures (particles, disks, pillars/wires etc.). We present an overview of our research on optical coatings based on semiconductor nanostructure assemblies focusing on their optical properties, different fabrication technologies and selected application examples. Design and simulations of the optical coatings are performed by finite difference time domain calculations, and are used as a guideline for fabrication. We discuss different routes for fabrication of nanostructured optical films/coatings including directed assembly and patterning of nanoparticles from solution phase, solution synthesis, combination of dry etching and colloidal lithography, transfer printing, and generation of flexible polymer films with embedded nanostructures. The fabricated films are validated by optical measurements and some device specific properties such as omni-directional broad-band anti-reflection in solar cells and efficient light extraction in light emitting diodes are demonstrated.

Stefan Breuer
Timing jitter and multi-gigahertz pulse train repetition rate control of a long monolithic multi-section quantum dot semiconductor laser
C. Weber, J. Javaloyes, O. Nikiforov, and S. Breuer
Technische Universität Darmstadt, Germany

Microwave/millimeter-wave signal generation and optical data communication applications demand compact, ultrafast and frequency agile mode-locked lasers. Monolithic semiconductor quantum dot lasers are attractive sources for such time-critical applications. Their repetition frequency is fixed by the laser cavity length and fine-tuning is limited. All-optical or opto-electrical laser stabilization schemes already allow for an improved frequency tuning, they however increase slightly the degree of complexity of the experiment. We present results on the timing jitter and repetition rate control of a monolithic mode-locked semiconductor laser by a specific absorber and gain section placement. We report on wide repetition rate frequency agility and substantial timing jitter reduction simply by gain current biasing.

Weng Chow
InGaAs quantum-dot micro-pillar emitters: From spontaneous emission and superradiance to lasing
W.W. Chow1, S. Kreinberg2, J. Wolters2, C. Schneider3, C. Gies4, F. Jahnke4, S. Höfling3,4, M. Kamp3, and S. Reitzenstein2
1Sandia National Laboratories, Albuquerque, USA
2Institut für Festkörperphysik, Technische Universität Berlin, Germany
3Lehrstuhl für Technische Physik, Universität Würzburg, Germany
4School of Physics and Astronomy, University of St Andrews, UK
5Institute for Theoretical Physics, University of Bremen, Germany

This talk discusses a theoretical and experimental study performed on AlAs/GaAs micropillars containing InGaAs quantum dots. The devices have the interesting property of having almost all emission (spontaneous and stimulated) channeled into one cavity mode. They are nice experimental platforms for studying laser physics because their emission behaviors question our understanding of lasing action. Analysis of spectrally-resolved photoluminescence and photon autocorrelation will be discussed.  A physically definitive criterion for lasing applicable to all systems will be presented.

Ramon Herrero
PT-axisymmetric VCSELs with linear central defect
W.W. Ahmed1, M. Botey1, R. Herrero1, and K. Staliunas1,2
1Departament de Física, Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
2Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
Semiconductor Lasers and particularly Vertical-Cavity Surface-Emitting Lasers (VCSELs) are important laser sources used for many purposes. However, the applications of these lasers are mainly restricted by their strongly multimode operation given by the lack of an intrinsic transverse mode selection mechanism [K. Iga, F. Koyama, and S. Kinoshita, IEEE J. Quantum Electron. 24, 1845 (1988)]. The introduction of an axial PT-symmetric potential within this kind of lasers is expected to induce a field enhancement and localization at the symmetry axis, central part of the laser. The required complex potential, combining a modulated refractive index and gain-loss distributions, may be achieved by different configurations with actual fabrication techniques.  The Complex Ginzburg-Landau equation is used as a simple VCSELs model, and the numerical results show important localization effects; due to the asymmetric mode coupling energy converges to the center leading to a strong light confinement. The main consequence is a narrow and bright laser emission from the central part of the device. As the system nonlinearities introduce saturation limiting the maximum intensity of the output beam, the inclusion of a central linear defect in the structure allows a larger field concentration.

Yasushi Iwata
Silicon cluster superlattice as a new nanomaterial for nanophotonics
Y. Iwata and N. Orita
National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan

Newly developed laser-ablation type cluster synthesis system generates an intense pulsed silicon cluster beam possessing a monodisperse size distribution. Direct deposition of the silicon cluster beam forms silicon cluster superlattice, where crystallographic coalescence between silicon clusters take places to form crystallographic unclosed-packed body center cubic superlattice structure with a lattice constant of 2.134±0.002 nm. Careful analyses of high resolution transmission electron microscopy (HRTEM) revealed that silicon clusters possess the sp3 diamond structure and their individual surfaces are successively extended and their crystalline axes are aligned following the superlattice axes [Y. Iwata, K. Tomita, T. Uchida, H. Matsuhata, Cryst. Growth Des. 15,2119-2128 (2015)].The crystallographically stable structure, electron density distribution, and electronic structures of silicon cluster superlattice have been explored with Ab-initio calculation based on the first principle with the OpenMX code. Resultantly, strong peaks of the surface states of silicon cluster superlattice appear in the density of state (DOS) on the Fermi level, the intensity of the DOS peaks is so high far from any surface density of states of not only bulk crystalline material but of usual nanomaterials. An experimental and theoretical investigation on the EELS imaging spectra have disclosed the existing of the new endogenous quantum surface states indigenous to silicon cluster superlattice. Strong electric field of e.g. the near field microscopy possibly excites the surface states effectively, and the network channels of the endogenous quantum surface states possibly induce or emit some effective electromagnetic fields in nanometer-scale appropriate for nanophotonics.

Julien Javaloyes
Electrical addressing and temporal tweezing of localized pulses in passively mode-locked semiconductor lasers
J. Javaloyes1, P. Camelin2, M. Marconi2, and M. Giudici2
1Departament de Física, Universitat de les Illes Baleares, Mallorca, Spain
2Université Côte d’Azur, CNRS, Institut de Physique de Nice, Valbonne, France

This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical-Cavity Surface-Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi-instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode-locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time-dependent current landscape.

Cristina Masoller
Are the spikes emitted by a semiconductor laser with feedback similar to neuronal spikes?
C. Quintero-Quiroz, T. Sorrentino, A. Aragoneses, M. C. Torrent, and C. Masoller
UPC, Barcelona, Spain
The nonlinear dynamics of a semiconductor laser induced by optical feedback has been intensively studied in the last three decades, not only because these lasers are important practical devices, but also, because of the wide range of complex dynamical regimes that are induced by feedback. In this contribution we focus on a regime known as low frequency fluctuations (LFFs), in which the laser emits a spiking output that resembles the spikes of biological neurons [C. Quintero-Quiroz et al., Characterizing how complex optical signals emerge from noisy intensity fluctuations, Sci. Rep. 6 37510 (2016)]. In this regime, semiconductor lasers have potential to act as ultra-fast photonic neurons, which can be building blocks of novel information processing systems [P.R. Prucnal et al., Recent progress in semiconductor excitable lasers for photonic spike processing, Advances in Optics and Photonics 8, 228 (2016)], inspired in the way biological neurons process information. In order to use the laser in the LFF regime as a basic information processing unit, it is crucial to understand how the information can be encoded in the output sequence of optical spikes [T. Sorrentino et al., The effects of periodic forcing on the temporally correlated spikes of a semiconductor laser with feedback, Optics Express 23, 5571 (2015)]. Here we present an experimental study of the statistical properties of the optical spikes, and compare them with neuronal spikes. We also consider the response to a weak periodic signal which is applied to the laser via direct current modulation. We analyze the signal waveform and laser operation conditions that optimize the entrainment of the output optical spikes to the input signal.
Wolfram Pernice
All-optical signal processing using phase-change nanophotonics
J. Feldmann1, M. Stegmaier1, N. Gruhler1, C. Rios2, C.D. Wright3, H. Bhaskharan2, and W.H.P. Pernice1
1Department of Physics, University of Münster, Germany
2Department of Materials, University of Oxford, UK
3College of Engineering, Mathematics and Physical Sciences, University of Exeter, UK

Photonic data storage would dramatically improve performance in existing computing architectures by avoiding time and energy consuming electro-optical conversion. To date, photonic memories have been predominantly volatile and lose their content if the input power is switched off. We exploit hybrid photonic-phase-change materials for realizing non-volatile, all-photonic memories and computing structures. By using optical near-field coupling we realize bit storage of up to eight levels in a single device that readily switches between intermediate states. We show that individual phase-change elements can be addressed through wavelength multiplexing, as well as through two-pulse encoding in waveguide arrays. Such multi-level, multi-bit devices provide a pathway towards eliminating the von Neumann bottleneck and point towards a new paradigm in all-photonic memory and non-conventional computing.

Ana Quirce
Simultaneous injection locking and polarization switching in VCSELs subject to parallel optical injection
A. Quirce1, A. Popp2, F. Denis-le Coarer2,3, P. Pérez2, Á. Valle2, L. Pesquera2, Y. Hong4, H. Thienpont1, K. Panajotov1,5, and M. Sciamanna3,6
1Vrije Universiteit Brussel, Faculty of Engineering Sciences, Brussels Photonics B-PHOT, Belgium
2Instituto de Física de Cantabria (CSIC-Univ. Cantabria), Santander, Spain
3OPTEL Research Group, LMOPS laboratory, Centrale Supélec, University of Paris-Saclay, and University of Lorraine, Metz, France
4School of Electronic Engineering, Bangor University, Wales, UK
5Institute of Solid State Physics, Sofia, Bulgaria
6OPTEL Research Group, LMOPS laboratory, Université de Lorraine, Metz, France
We report experimentally and theoretically a new state in which injection locking of the parallel polarization and simultaneous excitation of the orthogonal polarization in a single-transverse mode VCSEL are obtained. We found very simple analytical expressions for the power and phase of both linear polarizations. We demonstrate that the total power emitted by the VCSEL is constant and it does not depend on the injected power and on the frequency detuning. The stability maps in the injected power-frequency detuning plane identifying this state are found for different values of bias currents with good agreement between the experimental and calculated maps. A simple analytical expression describing the boundaries of these maps for negative and large frequency detunings provides a simple method to extract the linear dichroism of the laser.

Judy Rorison
Dilute bismide/ dilute nitride type II quantum wells: Novel strain balanced heterostructures for GaAs-based near and mid-infrared photonics
C.A. Broderick1, S. Jin2, I.P. Marko2, K. Hind2, P. Ludewig3, Z.L. Bushell2, W. Stolz3, E.P. O’Reilly4,5, K. Volz3, S.J. Sweeney1, and J.M. Rorison1
1Department of Electrical and Electronic Engineering, University of Bristol, UK
2Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, UK
3Materials Science Center and Faculty of Physics, Philipps-Universitat Marburg, Germany
4Tyndall National Institute, Cork, Ireland
5Department of Physics, University College Cork, Ireland

We demonstrate a new class of GaAs-based type II quantum wells based on the highly mis-matched III-V semiconductor alloys GaAs1-xBix and GaNyAs1-y.  We theoretically quantify and analyse the available design space for the growth of GaAs1-xBix/GaNyAs1-y type II structures on GaAs. Our calculations indicate that, for alloy compositions and layer thicknesses comparable with epitaxial growth, these heterostructures offer optical emission and absorption at wavelengths up to 3 µm as well as the ability to grow strain-balanced structures. We present the results of experimental measurements on a GaAs1-xBix/GaNyAs1-y (x=3.3%, y=6.25%) structure, grown via metal-organic vapor phase epitaxy. X-ray diffraction measurements indicate good structural quality, which is confirmed by the observation of photoluminescence and optical absorption at room temperature. The measured photoluminescence peak wavelength of 1.72 µm, which is in good agreement with theoretical calculations is, to our knowledge, the longest emission wavelength that has been observed to date using a pseudomorphically grown GaAs-based quantum confined heterostructure.

Tomasz Stefaniuk
Nanostructured optical components: New opportunities and limitations
T. Stefaniuk1,2, J. Pniewski2, M. Klimczak1, D. Pysz1, R. Stępień1, and R. Buczyński1,2
1Glass Department, Institute of Electronic Materials Technology, Warsaw, Poland
2Faculty of Physics, University of Warsaw, Poland

We report on our latest research in the field of nanostructured optical components fabricated using stack and draw technique. The concept of nanostructuring is based on the idea that the macroscopic optical properties of the system can be controlled by introduction of subwavelength elements. In some geometries even a single nanoinclusion can significantly change the performance of the device, in others incorporation of large amount of subwavelength elements justifies the usage of effective medium theory. Here, we demonstrate that nanostructurization through stack and draw method leads to development of fibres capable of efficient transferring and maintaining radial polarization and allows fabrication of elements of arbitrary effective index profiles.  We also discuss the impact of selective diffusion process on optical properties of systems and show that this mechanism can be considered either as an opportunity to extend the dispersion engineering flexibility in optical elements or as a limitation which introduces the uncertainty of the final dispersion profile of the nanostructured components.

Ganapathi Subramania
Topological photonic structures for nanophotonics
G. Subramania1 and P.D. Anderson1,2
1Sandia National Laboratories, Albuquerque, USA
2Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, USA

Topological photonic structures in analogy to their electronic counterparts can provide new functionalities in nanophotonics. In particular, they can possess topologically protected photonic modes that can propagate unidirectionally without scattering and can have an extreme photonic density of states (PDOS). These unique properties can directly impact many photonic systems in optical communications and in quantum information processing applications such as single photon transport. In analogy to spin Hall effect in electronics, photonic systems can exhibit helicity or pseudo-spin dependent light transport. Below we describe such a system in a honeycomb two-dimensional hole-array photonic crystal. Enabling such properties at optical frequencies and on chip-scale will be very important for practical applications of such phenomena.

Maria Tchernycheva
InGaN/GaN nanowire flexible light emitting diodes and photodetectors
Nan Guan1, Xing Dai1, Hezhi Zhang1, L. Mancini1, A. Kapoor2,3, C. Bougerol2,4, F.H. Julien1, N. Cavassilas5, M. Foldyna6, C. Durand2,3, J. Eymery2,3, and M. Tchernycheva1
1C2N site Orsay, UMR 9001 CNRS, Univ. Paris Sud, Univ. Paris Saclay, Orsay, France 
2Université Grenoble Alpes, Grenoble, France
3CEA-CNRS “Nanophysique et Semiconducteurs” Group, CEA-INAC-PHELIQS, Grenoble, France
4CEA-CNRS “Nanophysique et Semiconducteurs” Group, CNRS, Institut Néel, Grenoble, France
5Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, Marseille, France
6LPICM-CNRS, Laboratoire de Physique des Interfaces et Couches Minces, Ecole Polytechnique, Palaiseau, France

In this paper, we present our recent progress towards flexible nitride nanowire devices: we propose a method to combine high flexibility of polymer films with high quantum efficiency provided by nitride nanowires. The lift-off and transfer procedure allows to assemble free-standing layers of nanowire materials with different bandgaps without any constraint related to lattice-matching or growth condition compatibility. Following this method, we demonstrate blue, green, two-colour and white light emitting diodes as well as p-n photodiodes for integrable UVA sensors.

Shumin Wang
Electrically pumped GaAsBi laser diodes
Shumin Wang1,2, Xiaoyan Wu1, Juanjuan Liu1, Wenwu Pan1, Chunfang Cao1, Liyao Zhang1, Yuxin Song1, and Yaoyao Li1
1Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, China
2Department of Microtechnology and Nanoscience, Chalmers University of Technology, Goteborg, Sweden

In this paper, we present electrically pumped GaAsBi quantum well (QW) laser diodes (LDs) grown by molecular beam epitaxy. The LDs reveal a record long lasing wavelength of 1.14 µm at 300 K and can be operated under CW excitation up to 273 K. They also show high performance with an internal quantum efficiency of 86% and an internal optical loss of 10 cm-1. The characteristic temperature is 79 K in the temperature range of 225-350 K and the temperature coefficient of the lasing wavelength is 0.26 nm/K at 77-350 K, much smaller than 0.35-0.40 nm/K for InGaAs and InGaAsP QW LDs. These results suggest that GaAsBi LDs are attractive candidates for uncooled near infrared lasers on GaAs.

Christoph Weber
Multi-gigahertz picosecond pulse generation by passive mode-locking of monolithic two-section quantum well semiconductor lasers emitting at 1070 nm: Study of different laser lengths and gain-to-absorber section length ratios

C. Weber1, A. Klehr2, A. Knigge2, and S. Breuer1
1Institute of Applied Physics,Technische Universität Darmstadt, Germany
Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany

Monolithic two-section quantum well semiconductor lasers are promising sources for the generation of short pulses in the single-digit picosecond range by passive mode-locking and at high pulse repetition frequencies exceeding 40 GHz. Laser emission at around 1070 nm makes them ideal candidates for potential light amplification in Ytterbium doped fiber amplifiers and application in data transmission experiments. In both, a precise knowledge of the pulse train stability, quantified by timing-jitter and amplitude jitter, is crucial. We investigate lasers with different cavity lengths and gain-to-absorber section length ratios. For a large variety of biasing parameters, the pulse generation performance and pulse train stability is quantified.

NOA invited presentations:

Marcelo Abbade
Network performance of optical parametric amplifiers based on tellurite waveguides
J.D. Marconi1, M.L.F. Abbade2, E.A. de Mello Fagotto3, C.M. Serpa-Imbett4, P. Ferreira Pinto Neto2, and I. Aldaya5
1Universidade Federal do ABC (UFABC), CECS, Santo André, Brazil
2São Paulo State University (UNESP), Campus of São João da Boa Vista, Brazil
3Pontifical Catholic University of Campinas (PUC-Campinas), Campinas, Brazil
4University of Campinas (UNICAMP), School of Electrical and Computer Engineering, Campinas, Brazil
5University of Campinas (UNICAMP), “Gleb Wataghin” Institute of Physics, Campinas, Brazil

Optical parametric amplifiers (OPA) built on glass waveguides are tuneable devices that may be implemented as part of photonic integrated circuits. In this paper, we investigate the performance of recently proposed tellurite OPAs in transparent optical networks (TONs). The dispersion of these OPAs was engineered to provide high gain (~18 dB) and low ripple (~4.5 dB) over a bandwidth that is around three times wider than that offered by commercially available Erbium-doped fibre amplifiers. In particular, we analyse a scenario where wavelength division multiplexed (WDM) signals are transmitted through a TON equipped with tellurite two-pump OPAs (2P-OPA) to compensate the link transmission loss. Computer simulations are used to evaluate the influence of 2P-OPA crosstalk on the bit error rate (BER), as well as on the reach, of 243 quadrature phase-shift keying (QPSK) 56 Gbps signals that span over ~100 nm. Results indicate that by setting the launched optical power to -29 dBm per channel successful transmission in TONs with diameters as large as 1000 km can be achieved.

Juan Ania-Castañon
Distributed Raman amplification: Simulation and design optimisation in modern long-haul and unrepeatered systems (Tutorial)
J.D. Ania-Castañón, P. Rosa, G. Rizzelli, F. Gallazzi, and P. Corredera
Instituo de Óptica “Daza de Valdés”, CSIC, Madrid, Spain
Distributed Raman amplification has evolved considerably since it was first applied to optical communications. Simultaneously with their acceptance as an essential tool in extending capacity and reach of optical communications systems in a large number of practical scenarios, distributed Raman amplifiers have evolved in complexity, efficiency and performance. Due to the nature of distributed amplification, which affects the whole transmission span, system and amplifier design are inextricably linked, and numerical simulations play an critical role in finding the optimal solution for any set of system requirements. In this tutorial we will explain the basics of system design, illustrated with a few examples from recent research work.

Carmelo Bastos-Filho
Estimating the spectral gain and the noise figure of EDFA using artificial neural networks
E. de A. Barboza, J.F. Martins-Filho, and C.J.A. Bastos-Filho
Polytechnic School of Pernambuco, University of Pernambuco, Recife-PE, Brazil

In this paper, we propose a new approach to estimate the gain and the noise figure of EDFAs. This is an important tool for solving the adaptive control of operating point (ACOP) problem in optical amplifiers. The proposal uses an artificial neural network to enable a quick estimation of both amplifiers features requiring a small amount of memory. Results show that the neural network estimator is 80 times faster and uses 804 times fewer data than state of the art estimator, without losing significant accuracy. These advantages will help the use of iterative optimization techniques, like computational intelligence, to tackle the ACOP problem. Besides, it can assist in the implementation of ACOP approaches in simple devices like microcontrollers.

Vladimir Gordienko
Towards wide-bandwidth ultra-flat FOPAs
V. Gordienko, M. Stephens, and N. Doran
Aston Institute of Photonic Technologies, Aston University, Birmingham, UK

Fibre optical parametric amplifiers (FOPAs) offer the potential for high gain and >100 nm bandwidth at arbitrary wavelengths for increased transmission capacity. We will cover the main principles of the FOPA and discuss our approach to obtaining broad flat gain and performance improvement via simultaneous Raman amplification.

Igor Koltchanov
Efficient modeling of doped fiber lasers (Tutorial)
I. Koltchanov, VPIphotonics, Berlin, Germany
The presentation will provide an introduction to the theory of the doped fibers including equations for the doping ions' levels populations and radiation in the stationary and dynamic cases. After that, the modeling techniques required to simulate laser cavities in both frequency and time domains will be discussed. Furthermore, it will be shown how combining the fiber- and cavity models, as well as the models for other active/passive laser components enables simulation and design of important cw and pulsed fiber lasers, in particular, high-power cladding-pumped lasers, fiber lasers for sensing applications, Q-switched and mode-locked fiber lasers.

Pascal Landais
Phase sensitive amplifier using frequency-shift free optical phase conjugation for phase-regeneration of DPSK signals
A. Anchal, P. Kumar, and P. Landais
The Rince Institute, School of Electronic Engineering, Dublin City University, Ireland

We propose and numerically verify a scheme of phase-sensitive amplifier (PSA) using frequency-shift free optical phase conjugation. PSA is obtained by combining the conjugated wave with original signal. The frequency-shift free operation of phase conjugation helps in preserving the frequency of input signal during phase-sensitive amplification. The expression for PSA signal output and PSA gain are derived and it is analytically shown that PSA provides high gain for in-phase component and almost cancellation for quadrature-phase component of signal relative to pump phase under low pump power approximation. We prove theoretically that the proposed PSA provides 0 dB noise-figure with high gain-extension ratio. We study the performance of PSA under the effects of pump-signal detuning, amplifier length, input signal phase and signal power. Simulation results shows that PSA output is forced to attain 0 or pi phase regardless of large variation of phase in input signal. Nonlinear phase noise reduction of 40 Gbps DPSK signal transmitted over 1000 km standard single mode fiber confirms phase-regeneration by PSA.

Giuseppe Rizzelli
Raman cell optimisation for distributed amplification based transmission systems
G. Rizzelli, F. Gallazzi, P. Rosa, P. Corredera, and J.D. Ania-Castañón
Instituo de Óptica “Daza de Valdés”, CSIC, Madrid, Spain

Commercially available Raman fiber pumps display relatively high Relative Intensity Noise (RIN)that gets transferred to the output signal in systems relying on Raman distributed amplification. This has been shown to drastically hinder performance in Raman-based transmission systems [M. Krause et al., Pump-to-Stokes RIN transfer in Raman fiber lasers and its impact on the performance of co-pumped Raman amplifiers, Opt. Commun. 260(2), 656–661 (2006)], limiting the practically usable forward pump powers and setting constraints to the design of low signal power variation (SPV) bidirectional systems with optimised optical signal-to-noise ratios (OSNR) [M. Tan et al., Extended reach of 116 Gb/s DP-QPSK transmission using random DFB fiber laser based Raman amplification and bidirectional second-order pumping, in Optical Fiber Communication Conference 2015, W4E-1]. Recent works have highlighted a remarkable improvement in the resilience to RIN transfer of higher-order ultra-long Raman fiber lasers (URFL) in a random Distributed Feedback (rDFB) laser amplifiers configurations with no fiber Bragg grating (FBG) at the front-end [G. Rizzelli et al., Impact of input FBG reflectivity and forward pump power on RIN transfer in ultra-long Raman laser amplifiers, Opt. Express 24(25), 29170-29175 (2016)]. Moreover, we have shown [M. Tan et al., RIN mitigation in second-order pumped Raman fibre laser based amplification," in ACP Conference 2015, AM2E.6] that a low-reflectivity front-end FBG can be more beneficial than no back-reflections at all, for enhancing pumping efficiency while still keeping RIN transfer under control. Here we extend previous analysis of the low-reflectivity URFL amplification scheme including experimental investigation of RIN transfer, OSNR and pump power requirements for different architectures. We perform a comparison with the rDFB approach and present a detailed optimisation of the main amplifier parameters for the effective design of Raman-based transmission systems.

Mingming Tan
Raman fibre laser based amplification in long-haul/ unrepeatered coherent transmission systems
Mingming Tan1, P. Rosa2, M.A. Iqbal1, Son Thai Le3, I.D. Phillips1, S.K. Turitsyn1, and P. Harper1
1Aston Institute of Photonic Technologies, Aston University, Birmingham, UK
2The National Institute of Telecommunications, Warsaw, Poland
3Nokia Bell Labs, Stuttgart, Germany

The paper reviews the basic principles and recent advances of Raman fibre laser (RFL) based amplification techniques in long-haul/unrepeatered coherent transmission systems.  Different aspects of RFL based amplification have been characterised, including signal power distributions and relative intensity noise (RIN). Various RFL based amplifier designs have been evaluated in long-haul coherent transmission systems. The results shows the Fabry-Perot fibre laser based amplifier with two fibre Bragg gratings (FBGs) gives significant Q factor penalty using symmetrical bidirectional pumping, as the RIN of the signal is increased dramatically. However, random distributed feedback fibre laser based amplifier with a single FBG near the output section can mitigate the RIN of the signal, which enables the use of bidirectional second order pumping and therefore gives the best transmission performance up to 7915 km. Furthermore, using random DFB fibre laser based amplifier has been proven to be effective to combat nonlinear impairment. In addition, unrepeatered transmission over >350 km fibre length using RFL based amplification technique has been demonstrated experimentally using DP-QPSK WDM signals.

Feng Wen
Multilevel power transfer function characterization of nonlinear optical loop mirror
Feng Wen1,2, S. Sygletos1, C.P. Tsekrekos1, Xingyu Zhou2, Yong Geng2, Baojian Wu2, Kun Qiu2, and S.K. Turitsyn1
1Aston Institute of Photonic Technologies, Aston University, Birmingham, UK
2Key Lab of Optical Fiber Sensing and Communication Networks, Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China

The power transfer function of a nonlinear optical loop mirror (NOLM) is experimentally investigated for both continuous-wave and pulsed operation of the pump signal. The difference between transmission and reflection responses is discussed in view of using the interferometer for the amplitude regeneration of multilevel signals.

NetOrch invited presentations:

Rodolfo Alvizu
SDN-based network orchestration for new dynamic enterprise networking services
R. Alvizu1,2, G. Maier1,2, S. Troia2, Van Minh Nguyen1, and A. Pattavina1,2
1SWAN Networks,Milan, Italy
2Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Italy

Enterprise Networking (EN) services are source of high revenues for carriers. However, the traditional way of providing and selling those to enterprise and business customers is ossified and unsatisfactory for users. High prices, static connections and slow time to provision, make enterprise users doubtful about whether guaranteed connectivity is worth the price and push them to look for alternative solutions. That poses carriers at high risk of customer leak. This paper explains how SDN can foster the evolution of EN services in order to make them appealing again to enterprises. We propose an approach based on an SDN orchestrator as the enabling component of EN "4.0" services that are rapidly deployable, tailored to users' needs and dynamically configured. By global optimization of the core and the edge, a carrier can cut OpEx and increase margins. We present an early implementation of this concept, describing a demo-test in a simple virtualised but realistic network environment, showing new features and advantages for the carrier in terms of resource optimization.

Ramon Casellas
Experimental validation of the ACTN architecture for flexi-grid optical networks using active stateful hierarchical PCEs
R. Casellas1, R. Vilalta1, R. Martínez1, R. Muñoz1, Haomian Zheng2, and Young Lee3
1Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Castelldefels, Spain
2Huawei Technologies Co., Ltd.  Shenzhen, China
3Huawei Technologies, Plano, TX, USA

The Abstraction and Control of Traffic Engineered Networks (ACTN) defines the requirements, use cases, and an SDN-based architecture, relying on the concepts of network and service abstraction, detaching the network and service control from the underlying data plane. The architecture encompasses Physical Network Controllers (PNCs), responsible for specific technology and administrative domains, orchestrated by Multi-Domain Service Coordinator (MDSC) which, in turn, enables underlay transport resources to be abstracted and virtual network instances to be allocated to customers and applications, under the control of a Customer Network Controller (CNC). In this paper, we present the application of the ACTN architecture to the control of a multi-domain flexi-grid optical network, by proposing, adopting and extending i) the Hierarchical active stateful Path Computation Element (PCE) architectures and protocols ii) the PCEP protocol to support efficient and incremental link state topological reporting, known as PCEP-LS (PCEP link state), iii) the per link partitioning of the optical spectrum based on variable-sized allocated frequency slots enabling network sharing and virtualization, and iv) the use of a model-based interface to dynamically request the instantiation of virtual networks for specific clients / tenants. We report the design and the implementation of the testbed in order to validate the approach.

Andrea Fumagalli
A two-layer network orchestrator offering trustworthy connectivity to a ROS-industrial application
B. Mirkhanzadeh1, C. Shao1, A. Shakeri1, T. Sato2, M. Razo-Razo1, M. Tacca1, A. Fumagalli1, and N. Yamanaka2
1OpNeAR Lab, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, USA
2Department of Information and Computer Science, Keio University, Japan

This paper describes an experiment carried out to demonstrate robustness and trustworthiness of an orchestrated two-layer network test-bed (PROnet). A Robotic Operating System Industrial (ROS-I) distributed application makes use of end-to-end flow services offered by PROnet. The PROnet Orchestrator is used to provision reliable end-to-end Ethernet flows to support the ROS-I application required data exchange. For maximum reliability, the Orchestrator provisions network resource redundancy at both layers, i.e., Ethernet and optical. Experimental results show that the robotic application is not interrupted by a fiber outage.

Pablo Pavon-Marino
Dynamic QoS/QoE assurance in realistic NFV-enabled 5G access networks
J-J. Pedreno-Manresa1, P.S. Khodashenas2, M.S. Siddiqui2, and P. Pavon-Marino1
1 Universidad Politécnica de Cartagena, Spain
2 Fundació I2cat, Barcelona, Spain

Fifth generation mobile communication (5G) networks promise lower latency, higher traffic volume and data rates compared to what we see nowadays.  Among all technologies, Network Function Virtualization (NFV) and  Software Defined Networking (SDN) techniques over the cloud-enabled radio systems play an important role to enable resource pooling, scalability, layer interworking and spectral efficiency. Despite the potential benefits, there is always an additional challenge on assuring quality of service and user experience, especially on real life scenarios targeted by 5G. In this paper, we initially frame the dynamic QoS/QoE assurance problem; then with the help of simulation on a real life scenario, where ~100,000 persons get in and out of the Camp Nou stadium in Barcelona, we demonstrate the efficiency of our proposed QoS/QoE assurance algorithm.

Pontus Sköldström
DISMI – An intent interface for application-centric transport network services
P. Sköldström1, S. Junique1, A. Ghafoor1, A. Marsico2, and D. Siracusa2
1RISE ICT/Acreo, Kista, Sweden
2FBK CREATE-NET, Trento, Italy

Application-centric networking is a novel approach to construct transport networks that allows application-specific requirements to be taken into account through the entire service provisioning process: the service offered to each application is differentiated at each layer of the transport network, from IP to optical. This approach replaces the grooming of traffic with different requirements into a shared path in the transport layer, and allows for a finer control and utilization of network resources by network operators.  To make this concept viable, an interface for requesting a connectivity service by applications requires an abstraction with respect to the various underlying network technologies. Interfaces based on the concept of Intents provide such an abstraction: applications can describe what they need from the network (their requirements) rather than how to achieve them. This paper describes the design and implementation of the solution we propose: DISMI, the Intent-based North-Bound Interface of a network controller.

Salvatore Spadaro
Orchestrated SDN-based VDC provisioning over multi-technology optical data centre networks
S. Spadaro, A. Pagès, F. Agraz, R. Montero, and J. Perelló
Advanced Broadband Communications Centre (CCABA), Universitat Politècnica de Catalunya, Barcelona, Spain

In this paper, we describe some scenarios and technologies that have been proposed to cope with the requirements of current and next generation data centre infrastructure. In particular, we discuss the extensions that have been implemented at both orchestration and control levels to efficiently manage the data centres resources. We put the focus on the integration between the Orchestrator and the SDN Controller by describing the communication interfaces and their interaction to provision optimized Virtual Data Centres (VDC) instances over novel data centre infrastructure, with special mention to the different solutions adopted to manage multiple optical technologies at the data plane.

Luis Velasco
Brokered orchestration for end-to-end service provisioning across heterogeneous multi-operator networks
L. Velasco1, L. Gifre2, and A. Castro3
1Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
2Universidad Autonoma de Madrid (UAM), Madrid, Spain
3University of California (UC Davis), Davis, USA

This paper proposes a new networking paradigm introducing the broker-plane above the management planes of Autonomous Systems (ASes). The brokers communicate with the manager of each AS to coordinate end-to-end resource management and path provisioning across the multi-AS networks involving multiple operators. The broker plane updates the virtual network topology, manages the resource information of inter-AS links and aggregated (abstracted) intra-AS links, and computes end-to-end routing, modulation formats, and spectrum assignment (RMSA). To improve the grade of the inter-domain connectivity service, spectrum converters can be installed in inter-domain nodes or per-AS defragmentation can be performed with a global view. In this paper, we introduce a mechanism where each AS can advertise its internal capabilities, e.g., spectrum conversion, their ability to implement spectrum defragmentation or any other network feature. The Multi-AS RMSA with Defragmentation Capability problem is presented.

Akira Yamashita
Hadoop triggered opt/electrical data-center orchestration architecture for reducing power consumption
A. Yamashita1, W. Muro1, M. Hirono1, T. Sato1, S. Okamoto1, N. Yamanaka1, and M. Veeraraghavan2
1Keio University, Yokohama, Japan
2University of Virginia, Charlottesville, USA

In this paper, a data-center network (DCN) system that distinguishes Hadoop job types and allocates optical/electrical circuits to data flows depending on the types automatically is proposed. The proposed system calculates the predicted shuffle value (PSV) of the Hadoop job and determines which type of flow is allocated by comparing the PSV and the threshold value. The PSV can be calculated from a part of the input data based on the shuffle ratio, which is known to have a relationship to the heaviness of the shuffle phase of the Hadoop job. The threshold of PSV can be dynamically changed according to the network load condition to exploit the optical circuit efficiently. By orchestrating the DCN and the Hadoop system, the proposed system achieves the reduction of power consumption. In this study, the orchestration part of the proposed DCN system is implemented and the feasibility of switching data flows between optical and electrical circuits is verified.

Novel Glasses invited presentations:

Rolindes Balda
Site-selective luminescence of Nd3+ doped transparent oxyfluoride nano glass-ceramics
R. Balda1,2, G. Gorni3, J.J. Velázquez3, M.J. Pascual3, A. Durán3, and J. Fernandez1,2
1Departamento de Física Aplicada I, Escuela Superior de Ingeniería, Universidad del País Vasco UPV-EHU, Bilbao, Spain
2Materials Physics Center CSIC-UPV/EHU, San Sebastián, Spain
3Instituto de Cerámica y Vidrio (CSIC), Campus de Cantoblanco, Madrid, Spain

In this work, transparent oxyfluoride glass-ceramics obtained by the adequate heat treatment of Nd3+-doped glass with composition SiO2-Al2O3-Na2O-LaF3 are investigated. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM) show that the precipitated nanocrystals are LaF3 with a crystal size between 9-12 nm. Site-selective and time-resolved emission and excitation spectra of the 4F3/2 and 4F5/2 states, allow to unambiguously isolate the emission of Nd3+ ions in LaF3 nanocrystals which shows extremely well defined spectra, similar to those obtained for pure LaF3 crystal.  As the Nd3+ concentration is increased beyond 0.1 mol%, the luminescence quenching of lifetime for Nd3+ ions inside LaF3 crystals is observed to be stronger than for those dispersed in the glass matrix.

Trevor Benson
Modelling chaos in asymmetric optical fibres
D.S. Kumar1, S. Creagh2, S. Sujecki1, and T.M. Benson1
George Green Institute for Electromagnetics Research, Faculty of Engineering, Nottingham, UK
2 School of Mathematical Sciences, University of Nottingham, UK

A ray dynamical approach is developed for the study of large-core asymmetric step index fibres (SIF), especially those made from chalcogenide glasses (ChGs) which can exhibit very high refractive index, large numerical aperture, and which are transparent at mid-infrared wavelengths. The model allows for deformations of the SIF away from concentric circular structures, and for the light rays captured by the fibre to behave chaotically within the asymmetric boundaries of the fibre.  Chaotic and periodic rays can be classified by the Poincaré surface of sections (SOSs). In the model, the ray dynamics in the SIF are approximated by dividing the SOSs into pixels; the construction of a transfer matrix stores all the mapping probabilities. The light intensity distribution in the SOSs is efficiently propagated using the constructed transfer matrix, providing a viable alternative to propagating all the rays in the SIF by brute force ray tracing. The model enables the rapid calculation of the power accumulated in the fibre core following an arbitrary excitation.

Camille-Sophie Brès
Recent advances on nonlinear optics in silicon nitride waveguides
C-S. Brès1, A. Billat1, D. Grassani1, M.H.P. Pfeiffer2, and T.J. Kippenberg2
1Photonic Systems Laboratory (PHOSL), STI-IEL, Ecole Polytechnique Fédérale de Lausanne, Switzerland
2Laboratory of Photonics and Quantum Measurements (LPQM), SB-IPHYS, Ecole Polytechnique Fédérale de Lausanne, Switzerland

Nonlinear phenomena based on the material 2nd or 3rd order nonlinear susceptibility tensor χ(2) and χ(3), respectively, offer potential in a wide variety of applications by exploiting wave-mixing capabilities. The integration of these nonlinear effects at the chip scale represents the best path towards portable, compact and low power optical signal processing devices. A significant body of work has been done recently in this direction, in particular focusing on CMOS-compatible platforms. While many nonlinear effects have been demonstrated in Silicon, Silicon Nitride has recently sparked significant interest. Owing to a larger band gap, wide transparency window and low loss, the potential of SiN waveguides for linear and nonlinear optics is now well established. In this paper, we report recent results on nonlinear processes in SiN waveguides. In particular we will cover generation of an extremely broad supercontinuum extending 400 THz from the visible to 3.6 µm pumped by a turnkey telecom wavelength pulsed source. We will also report on a tunable pulse source based on dispersive wave generation in an engineered thick waveguide. Finally, we will show that SiN offers some interesting potential for χ(2) based nonlinear effects, an important step towards integrating second order nonlinearity on chip.

Reinhard Caspary
Universal fibre laser model used for the simulation of 2 µm thulium fibre lasers
R. Caspary1, R. Evert1, D. Pal2, A. Pal2, and R. Sen2
1Technische Universität Braunschweig, Institut für Hochfrequenztechnik, Germany
2CSIR-Central Glass and Ceramic Research Institute, Fiber Optics and Photonics Division, Kolkata, India

A universal simulation model for rare earth doped cw fibre lasers is presented. The model is based on generic rate and gain equations and therefore is very compact. It can be used for any fibre doped with one or several rare earth ions. The model allows for spectral simulations as well as radial discretization of the fibre. An algorithm was developed which optimizes the longitudinal fibre segmentation of the model.  Spectroscopic parameters for Thulium doped fibre lasers are taken from the literature or derived from calculations. Calculated multiphonon up-conversion rates take the thermalisation of closely spaced states into account. The simulation is compared with measurement results of a coupled wavelength shift observed in a tunable fibre ring laser. The simulation allows to investigate possible explanations and it indicates that the phenomenon is a measurement artefact.

Alessandro Chiasera
1D dielectric systems realized by RF-sputtering
A. Chiasera1, F. Scotognella2,3, S. Varas1, I. Kriegel4, G. Galzerano5, L. Criante3, A. Lukowiak6, D. Ristic7,8, L. Zur9,1, S. Taccheo10, M. Ivanda7,8, G.C. Righini9,11, R. Ramponi5, and M. Ferrari1,9
1IFN – CNR CSMFO Lab. & FBK CMM; Povo, Trento, Italy
2Politecnico di Milano, Dipartimento di Fisica and IFN-CNR; Milano, Italy
3Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Milan, Italy
4Department of Nanochemistry, Istituto Italiano di Tecnologia, Genova, Italy
5IFN – CNR and Politecnico di Milano, Dipartimento di Fisica, pMilano, Italy
6Institute of Low Temperature and Structure Research, PAS, Wroclaw, Poland
7RuđerBošković Institute, Division of Materials Physics, Laboratory for Molecular Physics, Croatia
8CEMS, Research unit New Functional Materials, Zagreb, Croatia
9Centro di Studi e Ricerche Enrico Fermi, Roma, Italy
10College of Engineering, Swansea University, Swansea, UK
11IFAC – CNR, MiPLab, Sesto Fiorentino, Italy

We demonstrate as the rf-sputtering technique is suitable for the fabrication of high quality multilayer structures based on glass matrix. This paper reports the steps used in the fabrication protocols and the optical, spectroscopic, structural and morphologic results of the samples. Various examples of systems prepared with this fabrication approach are presented with the aim of show the flexibility of the rf-sputtering to realize different devices to cover several photonic applications. In particular: (i) Erbium activated 1D photonic crystals, where it is possible to obtain coherent emission at 1.5 µm, are presented; (ii) multilayer structures with random thicknesses are first modelled and subsequently fabricated for application as broad band filters; (iii) uniform multilayer structure activated with Erbium ions where the stop band is designed to strongly modify the spectroscopic feature of the sample is fabricated and characterized. This research is performed in the framework of the projects: COST MP1401 “Advanced Fibre Laser and Coherent Source as tools for Society, Manufacturing and Lifescience” (2014 – 2018), PAS-CNR (2014-2016), Sustainable ManuFacturing – Cluster FabbricaIntelligente (2013-2016), MaDEleNA (2013 – 2016), PLANS - PLESC Centro Fermi.
Dominik Dorosz
Photoluminescence of antimony-germanate-silicate glass doped with europium ions and silver nanoparticles
J. Zmojda1, M. Kochanowicz1, P. Miluski1, R. Jadach2, W.A. Pisarski3, J. Pisarska3, M. Ferrari4,5, G. Righini5,6, and D. Dorosz2
Bialystok University of Technology, Poland
2AGH University of Science and Technology, Krakow, Poland
3Institute of Chemistry, University of Silesia, Katowice, Poland
4CNR-IFN, CSMFO Lab. and FBK-CMM, Povo-Trento, Italy
5 Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma, Italy
6MipLab.IFAC - CNR, Sesto Fiorentino, Italy

In the paper we are investigating the interactions between the europium ions and the silver nanoparticles embedded in an antimony-germanate-silicate glass. Modification of Sb2O3 - GeO2 – SiO2 - Al2O3 - Na2O glass system by AgNO3 (up to 0.4 mol.%) allows us to obtain a visible effect of thermo-chemical reduction of Ag+ ions and characteristic absorption band localized at the wavelength of 450 nm. The effect of Ag concentration on structural and luminescent properties of fabricated glasses doped with 0.2 mol. % Eu23 have been investigated. According to the luminescence analysis, in glass samples with Ag excited at 405 nm, the enhancement of 5D0 → 7F2 transition (616 nm) in Eu3+ ions has been observed just after the melting process. Based on these results, an effective embedding way of Ag particles in RE-doped optical fibers has been discussed.

Alexander Fuerbach
Novel mid-infrared fiber laser sources
A. Fuerbach1, S. Antipov1, D. Hudson1, M. Majewski2, and S. Jackson2
1Department of Physics and Astronomy, Macquarie University, Sydney, Australia
2Department of Engineering, Macquarie University, Sydney, Australia

We report on our research into fluoride fiber-based 3 μm class laser sources. Using holmium as the gain medium, record-high peak power levels are achieved in mode-locked laser systems that emit ultrashort pulses in the water vapor transmission window around 2.9 μm. Highly nonlinear and dispersion-engineered chalcogenide structures are utilized to extend the frequency range of those sources further into the mid-infrared. In addition, dysprosium-doped fibers are employed to demonstrate continuous-wave lasers that are tunable between 3 and 3.5 μm.

Pascal Masselin
New strategy for direct laser writing of low loss waveguide
P. Masselin1,2, E. Bychkov1, and D. Le Coq2
1Lab. Physico Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque, France
2Institut des Sciences Chimiques de Rennes, Université de Rennes 1, France

Two geometries are usually considered for direct laser writing of waveguide in glass that differ mainly from the way the sample is translated in regard to the laser beam propagation direction, namely transversely or longitudinally. In this contribution we report on waveguide of multi-core type composed of positive refractive index channel aligned on a hexagonal lattice and written using an alternative method. Every channel is obtained by stacking voxels of refractive index variation obtained by femtosecond laser pulse burst in a static position. The dimension of the core is determined by the number of channels and its refractive index contrast with the cladding is controlled by the laser burst duration. Therefore all the characteristics of the waveguide can be fully and independently accessed through simple experimental parameters. We apply this technique to waveguide writing in chalcogenide glass and show that the propagation loss can be reduced down to 0.11 dB/cm. Moreover repeated measurements during 18 month of this loss demonstrate the temporal stability of this value.

Leonid Mochalov
2D-layered As-S chalcogenide material with strong structural luminescence
L. Mochalov, A. Nezhdanov, and A. Mashin
Nizhny Novgorod State Technical University, Russia

The novel physical properties of two-dimensional and layered “beyond graphene” chalcogenide materials suggest a strong base to study new fundamentals underlying condensed matter physics. Among these materials layered arsenic monosulfide is a key to advancing 2-D photosensitive devices such and quantum computer. Here we demonstrated the synthesis of two dimensional arsenic monosulfide (As4S4) via interaction of elemental arsenic and sulphur in low-temperature non-equilibrium plasma discharge at low pressure. Moreover, we assume that plasma chemical vapor deposition is the one is the most promising method of tailoring of 2-D materials due to ceteris paribus the existence of two additional implements – temperature and concentration of electrons in plasma discharge. The optical and structural properties of the films were investigated. The data were analyzed and compared with the same obtained for thin films, prepared by different techniques. The strong structural luminescence phenomenon is observed. The possible mechanism formation of thin film structure was suggested.

Pavla Nekvindova
Erbium luminescence in various photonics crystalline and glass materials – A review
P. Nekvindova1, A. Mackova2, and J. Cajzl1
1Department of Inorganic Chemistry, University of Chemistry and Technology, Prague, Czech Republic
2Nuclear Physics Institute, Czech Academy of Sciences, v. v. i., Řež, Czech Republic

We would like to present the contribution dealing with relations between the luminescence of trivalent erbium ions and various crystal fields of photonics materials. Results of erbium doping of the conventional photonics materials such as lithium niobate, sapphire, zinc oxide and diamond, as well as various glasses, will be presented. The influence of erbium content and its position in material structure on the luminescence properties will be shown. For the glass materials the influence of glass matrices and the choice of sensitizer ions on the luminescence properties will be discussed. Additionally, for the crystalline materials, the theoretical models calculated using ab-initio DFT approach were created and will be discussed as well.

Pavel Peterka
Self-sweeping of laser wavelength and associated mode instabilities in fiber lasers
P. Peterka1, P. Honzátko1, J. Aubrecht1, P. Navrátil2, P. Koška1, F. Todorov1, O. Podrazký1, J. Čtyroký1, and I. Kašík1
1Institute of Photonics and Electronicsof the CAS, Prague, Czech Republic
2HiLASE Centre, Institute of Physics of the CAS, Za Radnici 828, 252 41 Dolni Brezany, Czech Republic
Fiber lasers may exhibit instabilities and self-pulsed regimes that can have catastrophic consequences on their components. One of the self-pulsing regimes is the recently observed spontaneous laser line sweeping (SLLS). The SLLS is characterized by periodic wavelength drift over broad spectral interval of several nanometers followed by quick bounce backward. The sweeping rate is relatively slow, of the order of nm per second. The SLLS can be explained by spatial-hole burning in the active fiber and it can be considered as a special case of instability of longitudinal modes of the laser cavity. Thanks to narrow linewidth and simple construction, the SLLS fiber lasers are attractive sources for testing of photonics components, interrogation of optical fiber sensor arrays and for laser spectroscopy. We review recent advances in investigation of the SLLS in fiber lasers including its effect on the triggering of the self-Q-switched regime and the generation of giant laser pulses.

Laeticia Petit
Novel Er3+ doped phosphate glass-ceramics for photonics
L. Petit1,2, H. Nguyen1, M. Hongisto1, T. Salminen1, T. Hakkarainen1, P. Lopez-Iscoa3, D. Pugliese3, N.G. Boetti4, and D. Milanese3,5
Photonics Laboratory, Tampere University of Technology, Finland
2nLIGHT Corporation, Lohja, Finland
3DISAT - Politecnico di Torino and INSTM, Torino, Italy
4Istituto Superiore Mario Boella, Torino, Italy
5IFN - CNR, CSMFO Lab., Povo-Trento, Italy

In this invited proceeding, we report our latest results on the development of Er3+ doped phosphate glass-ceramics. Those new glass-ceramics were processed using different techniques, such as direct doping of particles into the glass melt and glass-ceramics methods. First, we explain the challenges to balance the survival and dispersion of Er3+ doped particles when preparing phosphate glass-ceramics using the direct doping of particles. Then, we discuss the impact of the glass crystallization on the luminescence properties of Er3+ ions.

Diego Pugliese
Design, processing and characterization of custom phosphate glasses for photonic and biomedical applications
D. Pugliese1, N.G. Boetti2, E. Ceci-Ginistrelli1, D. Janner1, J. Lousteau3, and D. Milanese1,4
1Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino and INSTM, Italy
2Istituto Superiore Mario Boella, Torino, Italy
3Optoelectronics Research Centre, University of Southampton, UK
4Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Trento, Italy

Phosphate glasses (PGs) are promising host materials for the development of compact fiber amplifiers and lasers thanks to their good chemical durability, easy processing, outstanding optical properties, no clustering effect and very high solubility of rare-earth (RE) ions. Furthermore, some particular calcium-phosphate glasses exhibit unique dissolution properties in aqueous media with degradation rates that can be tailored by properly designing the glass composition. This feature makes them attractive biomaterials and allows the engineering of novel biomedical devices for deep-tissue diagnosis and therapy. In this work we will report the ongoing activities and the recent results obtained by our research group on the design, processing and characterization of novel custom phosphate glasses for both photonic and biomedical applications.

Sławomir Sujecki
Modelling of multimode selenide-chalcogenide glass fibre based MIR spontaneous emission sources
S. Sujecki, L. Sojka, E. Beres-Pawlik, R. Piramidowicz, H. Sakr, Z. Tang, E. Barney, D. Furniss, T.M. Benson, and A.B. Seddon
Department of Telecommunications and Teleinformatics, Faculty of Electronics, Wroclaw University of Science and Technology, Poland

Chalcogenide glass fibres have been demonstrated as a suitable medium for the realisation of spontaneous emission sources for mid-infrared photonics applications with a particular emphasis on sensor technology. Such sources give a viable alternative to other solutions due to potentially low cost, high reliability and robustness when pumped using commercially available semiconductor lasers. We present a comprehensive analysis of the properties of selenide-chalcogenide glass fibres applied as spontaneous emission sources. We extract the modelling parameters from measurements using in house fabricated bulk glass and fibre samples. We apply the well-established rate equations approach to determine the level populations, the distribution of the photon intensity within the fibre and the output power levels. We compare the modelling results with experiment.

Caroline Vigreux
First steps towards the realization of optical sensors to characterize spray deposits of pesticides on the leaves of vine plants
C. Vigreux1, M. Bathily1, R. Escalier1, R. Kribich2, A. Pradel1, and R. Bendoula3
1ChV team, ICGM, UMR CNRS 5253, Université Montpellier, France
2TéHO team, IES, UMR CNRS 5214, Université Montpellier, France
3ITAP group, IRSTEA, UMR 1201, Montpellier, France

The reduction of inputs is a strategic stake for the wine industry, the main consumer of plant protection products. The development of research / experimentation and technical transfer on this topic over the past few years reflect this ambition shared by all actors. If efforts are mainly based on finding alternative products or developing decision support tools (DAOs) to reduce doses of applied products, optimizing the quality of spraying is also an important lever and can be directly mobilized by the winegrowers. The "spray deposit" is an indicator that reveals the dose received locally by the various organs of the plant that the treatment aims to protect. Thus, the "spray deposition" measure provides valuable information for optimizing the use of inputs. At present, the measurement of this surface quantity (surface covered, size of drops) is based on a constraining and tedious implementation based on artificial collectors. This operation requires to install and then retrieve all the collectors (more than a hundred in general) completely manually. Then, the analyzes are done in laboratory, which mobilizes time, manpower and consumables. Thus, automation of this measure would make it possible to acquire more references mobilizable by the manufacturers of sprayers to optimize their machines and the farmers themselves with a view to defining more precisely the optimal dose to be used thus causing a reduction in the use of plant protection products. In this context, our objective would be to develop optical sensors to characterize the quantity and distribution of a liquid spray. These optical sensors will have waveguides as basic bricks: the idea will be to analyze the impact of a liquid spray on the surface of the guides on their light guiding properties.

OWW invited presentations:

Milorad Cvijetic
Characterization of free space optical channels for terrestrial and maritime air conditions
M. Cvijetic and Ming Li
University of Arizona, Tucson, USA

The efforts to increase the capacity of free space optical (FSO) channels are strongly dependent on the air conditions in the atmosphere. It is well known that absorption and scattering in atmosphere will cause attenuation of the light intensity, while clear-air atmospheric turbulence will eventually induce the wave-front distortions and intensity fluctuations.  Both the intensity attenuation and fluctuations are observed differently in terrestrial and maritime air conditions and will impose the limits to both the transmission distance and achievable bit rates. In this paper we characterize the impact of terrestrial and maritime air conditions and evaluate performance of high-speed systems operating through terrestrial and maritime FSO channels.

Goran Djordjevic
Analysis of mixed RF/FSO system with imperfect CSI estimation
M. Petkovic1, G.T. Djordjevic1, and I.B. Djordjevic2
1Faculty of Electronic Engineering, University of Nis, Serbia
2Department of Electrical and Computer Engineering, University of Arizona, Tucson, USA
In this invited paper, we present utilization of free-space optical (FSO) link in overcoming a connectivity gap between the backbone and last mile access networks. The non-line-of-sight area is bridged by radio frequency (RF) link by employing relaying technology, while the FSO link is used to deliver transmission from the relay to the end user. Firstly, a brief recapitulation of main results in the field of mixed dual-hop relaying RF/FSO system is presented. Further, the performance of mixed dual-hop amplify-and-forward (AF) relaying RF/FSO system is analysed. The outage probability expression of investigated system is provided, considering variable gain AF relay when channel state information (CSI) estimation is imperfect. The Nakagami-m fading environment is adopted for RF hop, while the intensity fluctuations of optical signal are assumed to origin from both atmospheric turbulence and pointing errors. Numerical results are presented and validated by Monte Carlo simulations. Effects of different system and channel parameters are observed. It is concluded that outdated CSI used for relay gain adjustment has an important impact on the mixed RF/FSO system performance.

Volker Jungnickel
Long-term outdoor measurements using a rate-adaptive hybrid optical wireless / 60 GHz link over 100 m
D. Schulz, V. Jungnickel, S. Das, J. Hohmann, J. Hilt, P. Hellwig, A. Paraskevopoulos, and R. Freund
Fraunhofer Heinrich Hertz Institute, Berlin, Germany

In this paper, we evaluate the potential of a rate-adaptive hybrid link, combining LED based optical wireless and 60 GHz technologies. These links over short backhauling distances are well suited for the deployment of small radio cells in 5G mobile networks. Results from a 4.5-month outdoor field trial indicate that the availability for both links is 100%. The throughput of the LED-based optical link is higher in 90% of all cases while the 60 GHz link has a higher minimal throughput. If both links are aggregated, the hybrid link offers minimal/average/maximal data rates of 230/750/880 Mbps over 100 m in all weather conditions.

Jan Latal
Measurement of changes of polarization of optical beam affected by atmospherically effects
J. Latal, J. Vitasek, L. Hajek, A. Vanderka, R. Martinek, and V. Vasinek
VSB-Technical University of Ostrava, Czech Republic

In this article the composite author dealt with measurement possibilities of polarization states of light source emitting 1550 nm which was affected by atmospherically transmission environment in special acrylate box 2.5 m long. The Polarimeter Thorlabs TXP 5004 and the External Sensor Head PAN5710IR3 measured the changes of polarization parameters, ellipticity and azimuth, defining placement on the Poincaré sphere for the light source emitting 1550 nm with marking ML925B45F. The statistical analysis was done from these parameters and by the help of testing of hypotheses was set, whether the difference between reference environment without turbulences and affecting of atmospherically effects is statistically significant..

Erich Leitgeb
Implementation of a testbed with a hardware channel emulator for simulating the different atmospheric conditions to verify the transmitter and receiver of optical wireless systems
E. Leitgeb, H. Ivanov, T. Plank, P. Pezzei, and C. Pock
Institute of Microwave and Photonic Engineering, Graz University of Technology, Austria

Related to different international activities in the Optical Wireless Communications (OWC) field Graz University of Technology (TUG) has high experience on developing different high data rate transmission systems and is well known for measurements and analysis of the OWC-channel. In this paper, a novel approach for testing FSO (Free Space Optical) systems in a controlled laboratory condition is proposed. Based on fibre optics technology, TUG testbed could effectively emulate the operation of real wireless optical communication systems together with various atmospheric perturbation effects such as fog and clouds. The suggested architecture applies an optical variable attenuator as a main device representing the tropospheric influences over the launched Gaussian beam in the free space channel. In addition, the current scheme involves an attenuator control unit with an external DAC (Digital Analog Converter) controlled by self-developed software. To obtain optimal results in terms of the presented setup, a calibration process including linearization of the non-linear attenuation versus voltage figure is performed. Finally, analytical results of the attenuation based on real and simulated measurements with the hardware channel emulator (the testbed) in a laboratory controlled environment are shown. The implementation can be used in further activities to verify OWC-systems, before testing under real conditions.

Joaquin Perez
On the evaluation of an optical OFDM Radio over FSO system with IM-DD for high-speed indoor communications
J. Perez1 , F.I. Chicharro1,2, B. Ortega1, and J. Mora1
1Photonics Research Labs (PRL), ITEAM Research Institute, Universitat Politècnica de València, Spain
2Institute for Multidisciplinary Mathematics IMM, Universitat Politècnica de València, Spain
A novel radio over fiber (RoF) and free space optics (FSO) hybrid system based on optical OFDM (OOFDM) signal transmission is proposed in this paper to provide high capacity optical wireless indoor communication links. A low cost transmission scheme based on IM-DD is proposed to simplify and reuse existing infrastructure to deploy a high bandwidth FSO link. This paper shows the experimental results based on the implementation of the proposed scheme under a 16-QAM OOFDM digital transmission over 10 km SMF and 300 mm FSO link. The results show the feasibility to deploy a 20 Gbit/s communication system over a 5 GHz RF bandwidth OFDM signal by using IM-DD scheme for the optical transmission without any optical multiplexing technique.

Murat Uysal
A custom-design atmospheric channel emulator for the performance evaluation of free space optical communication systems
B. Kebapci, F. Miramirkhani, H. Nouri, and M. Uysal
Centre of Excellence in Optical Wireless Communication Technologies (OKATEM), Özyeğin University, Istanbul, Turkey

Free space optical (FSO) communication systems can be used in a wide range of application areas including enterprise/campus connectivity, fiber back-up, backhauling for cellular networks, and airborne communications among others. With the recent increasing interest on this promising technology, there is a need for a comprehensive understanding of system limitations in practical propagation settings. Atmospheric attenuation of FSO links is dependent on weather conditions such as fog, rain, dust, and various combinations of each. Furthermore, FSO links experience atmospheric turbulence induced fading as a result of the variations in the refractive index. Due to the difficulty to predict the occurrence of specific atmospheric effects, and to repeat the measurements under the same conditions, it is highly desirable to quantify the FSO system performance in a controlled laboratory environment. In this paper, we present our custom design atmospheric channel emulator for FSO system evaluations in a controlled environment. Our emulator is in the form of an atmospheric chamber with dimensions of 60 cm x 40 cm x 300 cm. It is equipped with adjustable heaters, coolers and fans to create the turbulence. It also houses a fog generator and droplet watering system to generate different weather conditions. The conditions within the emulator are monitored through temperature, humidity, visibility, altitude, pressure, dust and wind speed sensors. Using this custom-design emulator, we experimentally investigate the performance of FSO links exploring the effects of different wavelengths and laser beam shapes. We further validate our results comparing to simulated propagation models in OpticStudio through ray tracing.

Jan Vitásek
Position of light sources for VLC
J. Vitasek, J. Latal, T. Stratil, S. Hejduk, A. Vanderka, and L. Hajek
VSB-Technical University of Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Telecommunications, Ostrava, Czech Republic

White LED diodes are increasingly used. Thanks their features they are also used for illumination and gradually replace the classical light bulbs and fluorescent tubes. The one of advantages of white LED diodes is their availability for the Visible Light Communication. This article deals with study of suitable placing of light sources for indoor. The aim is a uniform light distribution and thereby a uniform distribution of VLC data signals. There were created light sources with LED diodes in software LightTools. These light sources were placed on the ceiling of room. The simulation found the positions of light sources in which the light distribution was the most uniform.

Ke Wang
Short-range infrared optical wireless communications: Systems and silicon integration
Ke Wang1,3, Yang Wang1,2, Shitao Gao1,2, A. Nirmalathas2, C. Lim2, K. Alameh4, Hongtao Li3, and E. Skafidas2,5
1School of Engineering, Royal Melbourne Institute of Technology (RMIT) University, Australia
2Department of Electrical and Electronic Engineering, The University of Melbourne, Australia
3School of Electronic and Optical Engineering, Nanjing University of Science and Technology, China
4Electron Science Research Institute (ESRI), Edith Cowan University, Joondalup, Australia
5Centre for Neural Engineering (CfNE), The University of Melbourne, Australia

Short-range infrared optical wireless communications have been widely studied, to provide high-speed wireless connectivity in personal working and living spaces. In this paper, infrared short-range optical wireless communication systems and the integration of key functions such as the beam steering function on the silicon photonics platform are discussed.

Wen-De Zhong
Performance analysis of angle diversity multi-element receiver in indoor multi-cell visible light communication systems
Wen-De Zhong, Chen Chen, Helin Yang, and Pengfei Du
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore

An indoor visible light communication (VLC) system using white light-emitting diodes (LEDs) usually consists of multiple optical attocells, such that it can achieve full coverage of an indoor environment. The performance of an indoor multi-cell VLC system could be significantly degraded by inter-cell interference (ICI). To address the ICI issue, we propose and investigate an angle diversity multi-element receiver (ADMER) for indoor multi-cell VLC systems. Our proposed ADMER consists of one top detector and five side detectors, which is optimized in terms of the half-angle field-of-view (FOV) of all the detectors and the inclination angle of the side detectors so as to achieve optimal performance. Impact of receiver random rotation is taken into consideration and receiver optimization is executed by maximizing the achievable average signal-to-interference-and-noise ratio (SINR). Our studies show that an indoor multi-cell VLC system using the proposed ADMER can not only effectively mitigate the ICI, but also has excellent robustness against receiver random rotation.

Kyriakos Zoiros
FSO signal equalization using directly modulated SOA and dual MRR filtering
Zoe V. Rizou and K.E. Zoiros
Democritus University of Thrace, Department of Electrical & Computer Engineering, Lightwave Communications Research Group, Xanthi, Greece
Free Space Optical (FSO) communications are a promising alternative over conventional fiber- optic wired systems. The unobstructed employment of this technology critically depends on its robustness against atmospheric impairments, such as scintillation. A semiconductor optical amplifier (SOA) in conjunction with optical filtering can act as amplitude equalizer to restore the quality of the impaired FSO signal. In this paper we propose to exploit as hard limiter a SOA whose current is directly modulated by non-return-to-zero (NRZ) electrical data pulses that correspond to the distorted FSO signal components. Moreover, we employ after the SOA two microring resonators (MRRs), which are configured as notch filters and are detuned toward opposite sidebands to mutually compensate for the SOA bandwidth-limited modulation response. The simulation results demonstrate the capability of the SOA with dual MRR-based scheme to efficiently compensate for the scintillation-induced amplitude deviations and enhance performance.

PAM invited presentations:

Filippo Alpeggiani
Reconstructing the scattering matrix of photonic systems from quasinormal modes
F. Alpeggiani1,2, N. Parappurath2, E. Verhagen2, and L. Kuipers1,2
1Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology, the Netherlands
2Center for Nanophotonics, AMOLF, Amsterdam, the Netherlands

The scattering matrix, which relates the incoming and the outgoing light in optical systems, is a fundamental tool to quantitatively describe the properties of resonant systems. In particular, it enables the understanding of many photonic devices of current interest, such as photonic metasurfaces and nanostructured optical scatterers. In this contribution, we show that the scattering matrix of a photonic system is completely determined by its quasinormal modes, i.e., the self-sustaining electromagnetic excitations at a complex frequency. As a consequence, when the quasinormal modes are known, it is possible to express the entire scattering matrix only in terms of the complex eigenfrequencies and the far-field limit of the modal field. We present a practical method to do so, on the basis of temporal coupled-mode theory, which is directly applicable to an arbitrary number of modes and input/output channels. Our theory does not require any ad-hoc assumptions, such as the fitting of an additional nonresonant background. We validate and discuss the theoretical formalism with some illustrative examples. This demonstrates that the theory represents a powerful and predictive tool for calculating the highly structured spectra of resonant nanophotonic systems, and, at the same time, a key for unravelling the physical mechanisms at the heart of such intricated spectral structures.

Kyungwon An
Coherently pumped single-atom microlaser
Kyungwon An, Department of Physics and Astronomy, Seoul National University, Korea
We present a single-atom microlaser exhibiting superradiant lasing. It consists of a high-Q cavity and a supersonic beam of barium atoms, which enter the cavity one by one prepared in a superposition state with identical phase. Although there was only one atom at most in the cavity at any moment, we observed superradiant lasing: the cavity mean photon number grew as the square of the mean number of atoms injected into the cavity during the cavity decay time. When the superposition state phase was made random, the single-atom superradiant lasing disappeared, consistent to our expectation.

Mária Csete
Optimized plasmonic resonators to improve single-photon sources
M. Csete, A. Szenes, B. Bánhelyi, T. Csendes, and G. Szabó
Department of Optics and Quantum Electronics, SZTE University, Szeged, Hungary
Plasmonic nanoresonators were designed to enhance the excitation and emission of nitrogen (NV) and silicon (SiV) diamond color centers, which are capable of generating encoded information for quantum information processing applications. Singlets and dimers of spherical diamond core - metal shell as well as nanorod metal core - diamond shell type coupled systems were inspected. The Purcell factor, radiative rate enhancement and quantum efficiency were determined by extracting the total emitted, far-field radiated and metal absorbed power. The plasmonic resonator configurations including the composition, nano-object geometry as well as dipole orientation and location were optimized. Based on the products of the radiative rate enhancements achieved at the excitation and emission, nano-resonators composed of silver are the most promising candidates for enhancing diamond fluorescence.

Takehiro Fukushima
Approximation accuracy of Gaussian-optical approach applied to two-dimensional optical microcavities
T. Fukushima, Department of Information and Communication Engineering, Okayama Prefectural University, Japan
The Gaussian-optical approach is often used to obtain approximate solutions of stable periodic orbit resonances for two-dimensional optical microcavities of various cavity shapes. In this work, the accuracy of the approximate solutions is investigated systematically for simple two-mirror stable semiconductor optical microcavities. We examined the correlation coefficient between the mode intensity profile of approximate solutions and that of numerical solutions obtained using the Fox-Li approach. We found that degradation of the approximation accuracy due to deformation of the end mirrors increases as the beam spot size of the approximate solution increases.

Matteo Galli
High-Q/V photonic crystal cavities realized by an effective Aubry-André-Harper bichromatic potential
M. Galli1, A. Simbula1, M. Shatzl2, L. Zagaglia1, F. Alpeggiani3, F. Shäffler2, T. Fromherz2, and D. Gerace1
1Dipartimento di Fisica, University of Pavia, Italy
2Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria
3Center for Nanophotonics, FOM Institute AMOLF, Amsterdam, the Netherlands
4Stuttgart University, Germany

We report on the realization of high-Q/V silicon photonic crystal cavities with resonance wavelengths in the telecom window around 1.55 μm. The cavity designs are based on an effective Aubry-André-Harper bichromatic potential, defined by the superposition of two one-dimensional lattices with an incommensurate ratio between their periodicity constants. This peculiar confinement mechanism allows to achieve an ultra-high-Q factor and diffraction-limited mode volume. Several photonic crystal nanocavities in a silicon membrane geometry have been realized with measured Q-factors in the one million range, as determined by resonant scattering experiments. The generality of the proposed designs and their easy implementation and scalability make these results particularly interesting for realizing highly performing photonic nanocavities on different material platforms and operational wavelengths.

Michael Gorodetsky
Kerr soliton combs in crystalline microresonators pumped by regular multifrequency diode lasers
N.G. Pavlov1,2, G. Lihachev2,3, S. Koptyaev4, A.S. Voloshin2, A.D. Ostapchenko1,2, A.S. Gorodnitskiy1,2, and M.L. Gorodetsky2,3
1Moscow Institute of Physics and Technology, Russia
2Russian Quantum Center, Skolkovo, Russia
3Faculty of Physics, M. V. Lomonosov Moscow State University, Russia
4Samsung R&D Institute Russia, SAIT-Russia Laboratory, Moscow, Russia

Kerr frequency comb generated in ultra-high Q whispering gallery mode (WGM) microresonators is a promising light source for ultra-compact photonic devices due to its potential advantages of low power consumption and possibility of chip integration. We introduce a technique to stabilize and control effective generation of dissipative Kerr solitons (DKS) in nonlinear crystalline microresonators using regular commercial broad spectrum multi-frequency CW laser diodes (1550 nm; P ~ 200 mW), self-injection locked to magnesium fluoride microresonators (Q > 109).

Yury Rakovich
Linear and nonlinear optics of hybrid plexitonic nanosystems
D. Melnikau1, R. Esteban2,3, A.A. Govyadinov4, D. Savateeva1, T. Simon5, A. Sánchez-Iglesias6, M. Grzelczak3,6, M.K. Schmidt1, A.S. Urban5, L.M. Liz-Marzán3,6, J. Feldmann5, J. Aizpurua1,2, and Y.P. Rakovich1,2,3,7
Centro de Física de Materiales (MPC, CSIC-UPV/EHU), Donostia-San Sebastián, Spain
2Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain
3IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
4CIC NanoGUNE, Donostia-San Sebastián, Spain
5Ludwig-Maximilians-Universität München, Germany
6CIC biomaGUNE, Donostia-San Sebastián, Spain
National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Russia
We report our recent results of investigation of the interactions between localized plasmons in gold nanorods and excitons in J-aggregates. We were able to track an anticrossing behavior of the hybridized modes both in the extinction and in the photoluminescence spectra of this hybrid system.  We identified the nonlinear optical behavior of this system by transient absorption spectroscopy. Finally using magnetic circular dichroism spectroscopy, we show that nonmagnetic organic molecules exhibit magneto-optical response due to binding to a plasmonic nanoparticles. In our experiments, we also studied the effect of detuning as well as the effect of off- and on resonance excitation on the hybrid states.

Misha Sumetsky
Optical and acoustic modes in a bottle resonator with nanoscale radius variation
M. Sumetsky, Aston Institute of Photonics Technologies, Aston University, Birmingham, UK
An elongated bottle microresonator with parabolic nanoscale effective radius variation possesses series of dense and equally spaced optical eigenfrequencies. The separation of these frequencies can match the eigenfrequency of its axially symmetric acoustic mode. At very low temperatures corresponding to very high mechanical Q-factor of the resonator and low noise, the axial series of both optical and mechanical eigenfrequencies are well defined. Then, natural acoustic oscillation of the bottle resonator can parametrically excite optical modes and give rise to a highly equidistant and moderately broadband optical frequency comb. The teeth spacing of this comb is independent of the input laser power and the amplitude of mechanical vibrations. The acoustic mode required for the generation of this comb can be excited by the radiation pressure of an optical mode modulated with a natural mechanical frequency of the acoustic mode. Surprisingly, it is shown that in addition to acoustic bottle resonators (which are similar to optical bottle resonators) there exist antibottle resonators, which have the shape of a neck formed along the optical fiber, and, nevertheless, can fully confine acoustic modes.

Ya Sha Yi
Integrated subwavelength grating micro lens and metasurfaces
Ya Sha Yi and Mao Ye
University of Michigan, Dearborn, USA

Integrated subwavelength micro lens and metasurfaces have found a variety of applications in concentrating photovoltaics, imaging, display and biomedical field. In this talk, we will discuss our latest progress in this emerging field.

PICAW invited presentations:

Prince Anandarajah
Integrated optical frequency combs
P.M. Anandarajah1, G. Jain2, M.D. Gutierrez Pascual1,2, J. Bradell2, and F. Smyth2
1School of Electronic Engineering, Dublin City University, Ireland
2Pilot Photonics, Invent Centre, Dublin City University, Ireland

Optical frequency combs (OFCs) are a revolutionary light source for numerous applications due to their precisely spaced coherent optical wavelengths. his paper will focus on OFCs for employment in next generation dense/ultra-dense wavelength division multiplexed high-speed optical communication systems, which places stringent requirements on the OFC. These requirements include stability, linewidth, cost-efficiency, power consumption and form-factor. Monolithically integrated comb sources with simple and compact designs offer many of these features. In this work, the authors present a gain switched integrated optical frequency comb source encased in a high-speed temperature controlled butterfly package. Experimental results on characterisation and its application to various optical transmission systems will be presented.

Nicola Andriolli
Simultaneous data transmissions on engineered closely packed silicon-on-insulator waveguide arrays
P. Velha, I. Cerutti, and N. Andriolli
Scuola Superiore Sant’Anna, Pisa, Italy

Mode division multiplexing is a promising technique that enables highly parallel and compact on-chip optical communications, but its scalability has been hampered by the crosstalk so far. By exploiting supermodes in closely packed waveguide arrays, low crosstalk between waveguides can be achieved when phase mismatch condition is met.  This paper considers two techniques to achieve phase mismatch: waveguide non-uniformity and waveguide bending. The aim is to experimentally assess the BER performance on both straight and curved arrays of closely packed waveguides. Experimental results at 10 Gb/s demonstrate the simultaneous data transmission over different waveguides with a power penalty <0.5 dB at BER=10-9 in straight non-uniform arrays and sharp bends.

István Bányász
Recent progress in ion beam fabrication of integrated optical elements
I. Bányász1, G.U.L. Nagy2, V. Havranek3, V. Vosecek3, E. Agócs4, M. Fried4, V. Rakovics4, and S. Pelli5
1Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
2MTA Atomki, Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary
3Nuclear Physics Institute AV CR, Řež near Prague, Czech Republic
4Research Institute for Technical Physics and Materials Science, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary
5MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Sesto Fiorentino, Italy

Planar optical waveguides and Bragg gratings were designed and written in various optical crystals with medium energy ion implantation. Some examples of the fabricated integrated optical elements are presented in this article:  Planar optical waveguides fabricated in Er: LiNbO3 crystal by irradiation with 5 MeV N3+ ions, and Bragg gratings fabricated by multi-energy implantation into a silicon substrate with N+ ions in the 800 keV – 3.5 MeV energy range. The SRIM code was used for planning the optical elements. The ion implanted optical elements were tested by spectroscopic ellipsometry and visible and infrared reflectometry. The results show that the proposed fabrication methods can produce integrated optical elements of adequate parameters.

Tibor Berceli
Parasitic phase modulation in single drive Mach-Zehnder optical modulator
T. Berceli and N. Badraoui
Budapest University of Technology and Economics, Department of Broadband Infocommunications and Electromagnetic Theory, Hungary

The single drive Mach-Zehnder interferometer modulator is used basically for optical intensity modulation. It is well known that its modulation characteristic exhibits a significant nonlinearity at increased drive level. However, we draw the attention to the problem that the intensity modulation is associated with a parasitic phase modulation. In this paper we investigate the source of parasitic phase modulation and its effect on the resultant modulation characteristic.

Eric Cassan
Integration of semiconductor carbon nanotubes for photonic applications in silicon photonics
Weiwei Zhang1, E. Durán-Valdeiglesias1, Thi Hong Cam Hoang1, M. Balestrieri2, S. Serna1, C. Alonso-Ramos1, X. Le Roux1, A. Filoramo2, L. Vivien1, M. Gurioli3, E. Cassan1
1Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France
2CEA Saclay, IRAMIS, NIMBE (UMR 3685), Gif-sur-Yvette, France
3Dep. of Physics, University of Florence, European Laboratory for Non-linear Spectroscopy, Sesto Fiorentino, Italy

This conference talk will sum up our recent contributions related to the integration of semiconductor carbon nanotubes (s-SWNTs) as an active material in silicon photonics. This work is motivated by the possible use of s-SWNTs for light emission, detection, and modulation relying on the same hybrid on-silicon integration platform. We will first describe experimental results carried out to prepare high quality thin polymer layers doped with purified s-SWNTs . Our efforts to integrate this effective active material in silicon photonic resonators and nanocavities will be then described. We report  cavity enhanced near infrared emission from nanotubes accompanied with a spectral narrowing effect when increasing pumping power levels and a threshold-like behavior regarding device light emission.

Sébastien Cueff
Ultra-compact polarization-insensitive integrated multimode interference beamsplitters
S. Cueff, Xuan Hu, J-J. Rolos, P. Rojo Romeo, and R Orobtchouk
Ecole Centrale de Lyon, France

Modern telecommunications systems and data centers extensively use photonics to guide, modulate and detect signals in the optical domain. In that context, Silicon photonics is poised to replace electronics and first generation optical links to efficiently transmit data at very high speed. To this end, large scale photonic integrated circuits require compact, low-loss and broadband building blocks on silicon platforms. Among other required functionalities, it is extremely important to efficiently split or combine guided light waves. A non-exhaustive list of devices using light splitting or coupling includes NxN switches, Mach-Zehnder Interferometer or 3 dB-couplers. Multimode interference optical devices (MMI) have unprecedented advantages for these functionalities in terms of robustness, compactness, low-loss and large bandwidth. In this communication, we report on the design and experimental demonstration of efficient MMI beamsplitters that are simultaneously ultra-compact, polarization-insensitive and broadband. Using a home-made full-vectorial mode-solver and a mode-matching technique, we provide a detailed explanation on how to model and optimize such a MMI beamsplitter. As a first experimental proof-of-principle, we fabricated a 1x2 MMI beamsplitter whose footprint is 2.4 x 4.3 µm2 and for which we demonstrate polarization-insensitive response for the wavelength range 1520 – 1620 nm. We further discuss general design rules to obtain polarization-insensitivity of MMI in various nanophotonic platforms, including functional oxide-based slot waveguide.

John Donegan
Novel polarization beam splitter based on p-i-n structure for an indium phosphide platform
N. Abadia, Xiangyang Dai, Qiaoyin Lu, Wei-Hua Guo, E. El-Fiky, D.V. Plant, and J.F. Donegan
Semiconductor Photonics Group, School of Physics and CRANN, Trinity College, Dublin, Ireland

In this paper, a polarization beam splitter (PBS) based on the indium phosphide (InP) platform is presented. The main advantage of the device is that the tight fabrication tolerances of fully passive devices can be overcome by adjusting two voltages in an easy calibration. To produce the splitting function, the Pockels effect and the plasma dispersion effect are exploited in the phase shifters of a symmetric 1x2 Mach-Zehnder interferometer (MZI). The experimental results show that such a device operating at 1550 nm has an on-chip loss of 3.5 dB and a polarization extinction ratio better than 15 dB. Keywords: optoelectronics, photonic integrated circuits, integrated optical devices, polarization-selective devices, polarization beam splitters, indium phosphide.

Maria Rute Ferreira André
Performance assessment of a QPSK coherent demodulator based on organic-inorganic hybrids
A.R.N. Bastos1-3, A. Shahpari2,3, L.D. Carlos1, M. Lima2,3, P.S. André4, and R.A.S. Ferreira1
1Physics Department and CICECO - Aveiro Institute of Materials, University of Aveiro, Portugal
2Instituto de Telecomunicações, University of Aveiro, Portugal
3Department of Electronics, Telecommunications and Informatics and Instituto de Telecomunicações, University of Aveiro, Portugal
4Department of Electrical and Computer Engineering and Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisboa, Portugal

Coherent optical systems offer enhanced possibilities to increase data transmission capacity. To implement these systems, optical demodulators are required to decode the data. In this context, optical demodulators for a Quadrature Phase Shift Keying (QPSK) modulation based on 90º hybrid couplers are presented. The devices were produced by direct UV-laser patterning on sol-gel derived organic-inorganic hybrids, and the input-output ports transfer function revealed the dependence of the optical signal phase. Therefore, QPSK symbols were decoded, and the associated constellation diagram was analysed in real-time. To assess the device performance the error vector magnitude and phase deviations were obtained (5% and 1°, respectively) making the produced device a promising choice to replace current QPSK receivers.

Fatima Gunning
Enabling photonic technologies at 2 microns
N. Kavanagh1, B. Murray1, D. Goulding1,2, P.E. Morrissey1, R. Sheehan1, B. Corbett1, and F.C. Garcia Gunning1
Tyndall National Institute, University College Cork, Ireland
2 Centre for Advanced Photonics and Process Analysis (CAPPA), Cork Institute of Technology,  Ireland

In this paper, we demonstrate optical injection locking in the 2 µm wavelength region between two discrete semiconductor lasers. We will highlight how such behaviour can be used as a key enabling technology in this new wavelength window, motivated by system improvements such as better filtering and linewidth reduction for advanced modulation formats.

Ronald Kaiser
CL-TWE Mach-Zehnder modulators on InP: Central elements in transmitter PICs of increasing complexity
R. Kaiser, S. Lange, M. Rausch, B. Gomez Saavedra, M. Gruner, G. Fiol, K. Janiak, A. Aimone, K.-O. Velthaus, J.H. Choi, and M. Schell
Fraunhofer Heinrich Hertz Institut, Berlin, Germany

The development of advanced InP-based transmitter PICs of increasing complexity and integrating periodically capacitive-loaded (CL) Travelling Wave Electrode (TWE) Mach-Zehnder modulators is reported and discussed in examples.

Floris Laporte
Reservoir computing with signal-mixing cavities
F. Laporte1, J. Dambre2, and P. Bienstman1
Photonics Research Group, UGent – imec, Belgium
IDLab, UGent - imec, Belgium
In an age where we get swamped by big data, new machine learning techniques for efficient high-speed data processing become more important than ever. One of these techniques, known as reservoir computing, is specifically designed for processing time-dependent data. We propose some new ideas for implementing such a reservoir computer on a silicon photonics chip for low-power and high-bandwidth optical communication applications. Our simulations show that this photonic reservoir can for example be used in pattern recognition tasks such as header recognition.

Goran Mashanovich
Germanium and silicon photonic integrated circuits for the mid-infrared
G.Z. Mashanovich, C.G. Littlejohns, D.J. Thomson, W. Cao, T. Li, A. Z. Khokhar, S. Stankovic, J. Soler Penades, Z. Qu, C.J. Mitchell, F.Y. Gardes, A C. Peacock, A.P. Knights, and M. Nedeljkovic
University of Southampton, UK

Silicon and germanium are transparent up to approximately 8 µm and 15 µm, respectively, thus offering a range of applications in biochemical and environmental sensing, medicine, astronomy and communications. In this paper we present our recent results on germanium and silicon modulators and detectors suitable for mid-infrared communications.

Pascual Muñoz
State of the art of silicon nitride photonics integration platforms
P. Muñoz1,2, D. Doménech1, C. Domínguez3, G. Micó2, L. Bru2, D. Pastor2
1VLC Photonics S.L., Valencia, Spain
2Universitat Politècnica de València, Spain
3Insitut de Microelectrònica de Barcelona - Centro Nacional de Microelectrónica - CSIC, Spain

Silicon Nitride photonics has received considerable interest in the past ten years, owing to its large transparency range from visible to the long near infrared, and superior performance compared to silicon in terms of non-linear phenomena.  In this paper we review the present state of the art of Silicon Nitride integration platforms, and provide design rules supported by experimental data for the design and manufacturing of photonic integrated circuits in these platforms.

Aleksander Smirnov
Second-harmonic generation by resonant high-index dielectric nanoparticles
L.A. Smirnov and A.I. Smirnov
Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia

By combining analytical and numerical approaches, we study resonantly enhanced second-harmonic (SH) generation by individual high-index dielectric nanoparticles made of centrosymmetric materials. Considering both bulk and surface nonlinearities, we describe second-harmonic nonlinear scattering from a silicon nanoparticle optically excited in the vicinity of the magnetic and electric dipole resonance. We discuss the contributions of different nonlinear sources and the effect of the lowest-order optical Mie modes on the characteristics of the generated far-field. Our findings uncover important implications for design of nonlinear nanoantennas fully integrable with silicon-based photonic circuits.

Isaac Suárez
Optimization of semiconductor halide perovskite layers to implement waveguide amplifiers
I. Suárez1, T. Tuyen Ngo2, E.J. Juárez-Pérez2, G. Antonicelli3, D. Cortizo-Lacalle3, A. Mateo-Alonso4, I. Mora-Seró2, and J.P. Martínez-Pastor1
1UMDO, Instituto de Ciencia de los Materiales, Universidad de Valencia, Spain
2Photovoltaics and Optoelectronic Devices Group, Departament de Física, Universitat Jaume I, Castelló, Spain

3POLYMAT, University of the Basque Country UPV/EHU, Donostia-San Sebastian, Spain
4Ikerbasque, Basque Foundation for Science, Bilbao, Spain
Semiconductor organometallic halide (CH3NH3PbX3, X=Cl, Br, I) perovskites (HPVK) have been emerged a potential gain media to construct a new generation of active photonic devices. Indeed, during the last three years a significant effort has been carried out to implement HPVK-based optical amplifiers or lasers with improved quality factors. In particular, minimization of the threshold of stimulated emission has been an important concern to decrease the power consumption, and hence to enhance the performances of the device. For this purpose strategies include a suitable integration of the semiconductor in a photonic structure, or the optimization of the material. Here we propose a novel approach to develop optical amplifiers by an appropriate passivation of HPVK layers incorporated in an optical waveguide. For this purpose, geometrical parameters were firstly properly optimized to demonstrate amplification of stimulated emission with a threshold as a low as 2 nJ. In addition, the passivation of traps of the semiconductor by introducing organic additives (twisted hexaazatrinaphthylene and bisthiadiazolefused tetraazapentacenequinone) resulted in a further reduction of the threshold (down to four fold). These results provide a novel scheme to enhance the applications of perovskite active devices.

Dimitris Tsiokos
Low-cost vertical coupling schemes for optical I/Os and 3D integration in CMOS photonic integrated circuits
D. Tsiokos1, G. Dabos1, J. Bolten2, and N. Pleros1
Center for Interdisciplinary Research and Innovation, Aristotle University of Thessaloniki, Thessaloniki, Greece
AMO GmbH, Aachen, Germany
Grating coupler structures have attracted prominent research and development efforts in order to address off-chip, vertical light coupling enabling wafer-level test and measurement as well as complex optical assemblies. In fact, three-dimensional (3D) integration is introduced as the key enabling technology for low footprint, high frequency and low loss silicon photonic and opto-electronic integrated circuits. Towards this direction, low-cost and CMOS compatible fabrication processes are required for the cost-effective mass-manufacturing of silicon photonic devices by CMOS foundries. This paper presents the recent research outcomes of PhosNET group on effective perfectly normal and off-normal grating couplers designed and fabricated on silicon-on-insulator (SOI) and Si3N4 platforms following low cost methodologies that comply with CMOS fabrication processes while minimizing lithography and etching steps.

Shogo Ura
Guided mode resonances in two-story waveguides
S. Ura1, K. Yamada1, Kyu Jin Lee2, R. Magnusson2, K. Kintaka3, and J. Inoue1
1Kyoto Institute of Technology
2The University of Texas at Arlington
3National Institute of Advanced Industrial Science and Technology

A guided-mode resonance wavelength filter consisting of a sub-wavelength grating on a waveguide shows interesting characteristics including very narrow bandwidth and polarization selectivity. Resonance behaviors in two story waveguides are introduced and discussed with new features and potential applications. Utilization of multiple guided modes is expected to provide a flat-top narrow band-stop filter suitable for WDM systems.

Quantum Photonics invited presentations:

Daryl Beggs
Optimised chiral light-matter interactions at polarisation singularities for quantum photonics
D.M. Beggs1, B. Lang2, and R. Oulton2
1Cardiff University, UK
2University of Bristol, UK

Photonic crystal waveguides support chiral-point polarisation singularities which give rise to local chirality even in the absence of a global chiral symmetry.  Placing a quantum dot at such a C-point gives rise to a uni-directional emission dependent on the electron spin – ideal for applications in quantum information as it entangles the spin direction of electrons on the quantum dot (static qubits) to the path in the waveguide (flying qubits).  Here we discuss the optimisation of this chiral light-matter interaction using slow-light waveguides, and show designs with 8.6 times enhancement of the local density of optical states at a C-point.

Wolfgang Elsäßer
Quantum optics of and with superluminescent diodes: The Hanbury-Brown and Twiss experiment in its 61th anniversary
W. Elsäßer, Institute of Applied Physics, Technische Universität Darmstadt, Germany
We start with a high historical review appreciating and emphasizing the importance and relevance of the Hanbury-Brown and Twiss (HBT) experiment for nowadays quantum optics. Then, we investigate within a modern and sophisticated version of the HBT experiment the quantum optical properties of optoelectronic quantum dot based superluminescent diodes (SLDs). The demonstrated fully incoherence of Broad-Area SLDs, the world’s most compact, ultra-miniaturized light source will be exploited in a classical ghost imaging (GI) scheme and finally, we discuss its functionalities and applications.

Alessandro Gaggero
Single- and multi-photon counting using an array of SNSPDs
A. Gaggero, F. Chiarello, M. Elviretti, M. Graziosi, F. Mattioli, G. Torrioli, and R. Leoni
Institute for Photonic and Nanotechnology (IFN-CNR), Rome, Italy
We report on the design, fabrication and electro-optical characterization at T=2.9 K of a photon number resolving detector designed to obtain a pulse-position resolution. This pulse-position-resolving detector (PPRD) is based on the spatial multiplexing of four superconducting nanowire avalanche photodiodes (SNAPs) connected in series. We choose to exploit the 2-SNAP configuration (i.e., 2 connected in parallel nanowires) to improve the signal-to-noise ratio (SNR) of the PPRD. Each pixel (i.e., a 2-SNAP) has in parallel AuPd resistor Ri (with i=1, 4) of different value. As a result of a detection event, each pixel produces a pulse with peak voltage IbRi, allowing in this way position resolution of the detection event.

Jean-Michel Gérard
Cavity switching: A novel resource for solid-state quantum optics
T. Sattler1, E. Peinke1, J. Bleuse1, J. Claudon1, W.L. Vos2, and J.M. Gérard1
1CEA/INAC, Grenoble, France
2Twente University, MESA+, COPS team, Enschede, Netherlands

We present switching experiments performed on pillar microcavities containing a collection of quantum dots (QDs). Switching events are probed using QD luminescence, after ultrafast optical injection of free carriers. We observe large switching amplitudes (by as much as 20 linewidths), as well as differential switching of the pillar modes under inhomogeneous pumping. Through transient coupling of QDs with a cavity mode, cavity switching is used for the first time to generate ultrashort (down to 4ps!) pulses of spontaneous emission. Beyond this application, cavity switching can be used more generally to control CQED effects in the time domain.

Marco Liscidini
Generation of energy-entangled W states
M. Menotti1, L. Maccone1, J.E. Sipe2, and M. Liscidini1
1Department of Physics, University of Pavia, Italy
2Department of Physics, University of Toronto, Canada

Tripartite entangled states, such as Greenberger-Horne-Zeilinger (GHZ) and W states, are appealing for tests of fundamental aspects of quantum mechanics, as well as for implementations of quantum communication protocols. While the information is typically encoded in the polarization or path of the photons, we propose a feasible scheme to generate W states that are entangled in the energy degree of freedom. This is achieved by propagating photon pairs generated by parametric fluorescence in a linear optical circuit and post-selecting on the output channels. Such source can be easily integrated, profiting from high stability and a compact footprint. We also present a simple protocol to characterize the generated tripartite state, which is based on the reduced density matrix approach. Unexpectedly, although we rely on the energy degree of freedom, the full state tomography does not require any frequency conversion.

Stephen Lynch
Solid state superatoms: Rydberg excitons in cuprous oxide
S.A. Lynch, C. Hodges, W.W. Langbein, M.P.A. Jones, and C.S. Adams
School of Physics and Astronomy, Cardiff University, UK

Creating isolated, two-level quantum systems (qubits) that can be coupled to perform gate operations or study many-body quantum systems is one of the outstanding goals in quantum information science. In cold-atom systems, Rydberg states have been used to create and coherently control non-classical states of light and atoms. Is there a way of combining the proven successes in cold-atom systems with the benefits of solid-state scalability? Rydberg excitons in cuprous oxide provide a potential route towards a new hybrid quantum technology. A major breakthrough by the Dortmund physics group in 2014 showed that robust high principal quantum number excitons could be realised in cuprous oxide, and the same group provided the first evidence of Rydberg blockade in this material. We have recently observed high principal quantum number excitons in cuprous oxide with N = 14, and our measurements are comparable to the state-of-the-art result achieved by the Dortmund group with white light excitation.

Ruth Oulton
Deterministic giant photon phase shift from a single charged quantum dot
P. Androvitsaneas1, A.B. Young1, J.M. Lennon1, C. Schneider2, S. Maier2, J.J. Hinchliff1, G.S. Atkinson1, E. Harbord1, M. Kamp2, S. Höfling2,3, J.G. Rarity1, and R. Oulton1
1Quantum Engineering Technology Labs and Quantum Engineering Centre for Doctoral Training, H. H. Wills Physics Laboratory and Department of Electrical & Electronic Engineering, University of Bristol, UK
2Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Center for Complex Material Systems, Universität Würzburg, Germany
3School of Physics and Astronomy, University of St Andrews, UK

QDs can be incorporated into solid state photonic devices such as cavities or waveguides that enhance the light-matter interaction. A near unit efficiency light-matter interaction is essential for deterministic, scalable quantum information (QI) devices [C.Y. Hu et al., Phys. Rev. B 78, 085307 (2008)]. In this limit, a single photon input into the device will undergo a large rotation of the polarization of the light field due to the strong interaction with the QD. In the past hopeful preliminary results have indicated that a low Quality-factor (Q~290) pillar microcavity possesses a high β-factor and that the instantaneous interactions should be deterministic and with high fidelity [P. Androvitsaneas et al., Phys. Rev. B 93, 241409(R) (2016)]. Here we measure the instantaneous response of the device and a macroscopic (~2/3 π or ~120o) lower bound for the phase shift of the reflected light as a result of the interaction is measured [P. Androvitsaneas et al., arXiv:1609.02851(2016)]. We are able to measure this large angle by measuring the phase shift over timescales shorter than the time for spectral diffusion (100μs). To do this we monitor times when the count rate of the cross-polarized channel is high and the co-polarized channel is low.

Wolfram Pernice
Ultrafast waveguide integrated single photon detectors
W. Pernice, Karlsruhe Institute of Technology (KIT) and University of Muenster, Germany
Single photon detectors based on superconductor nanowires (SNSPDs) provide high efficiency and good timing performance, as well as broad optical detection bandwidth. To move towards applications in high bandwidth quantum communication and processing, ultrafast detectors with high efficiency are needed. We realize compact SNSPDs with sub-micrometer effective length by aligning the nanowire perpendicular to nanophotonic waveguides. By integrating the nanowire into a photonic crystal cavity, we recover high absorption efficiency, thus enhancing the detection efficiency by more than an order of magnitude. The detectors possess sub-nanosecond decay and recovery times, and thus show potential for GHz count rates.

Roberta Ramponi
Femtosecond laser micromachining: An enabling tool for quantum technologies
R. Ramponi, Department of Physics, Institute for Photonics and Nanotechnology (IFN‐CNR) and Politecnico di Milano, Italy
Femtosecond‐laser micromachining is an enabling technology that allows maskless realization of fully integrated photonic, microfluidic and micromechanical devices. Indeed, direct femtosecond laser writing can be used in transparent materials both for the fabrication of high‐quality waveguides, and, possibly combined with chemical etching, for the realization of microfluidic channels. Moreover it can be used for surface structuring and functionalization, for the realization of high aspect‐ratio microholes and microchannels by direct surface ablation, and for the fabrication of 3D micro/nanostructures by means of two‐photon‐polymerization. In this presentation, the basics of femtosecond laser writing will be summarized, and the main aspects influencing induced material modifications will be discussed. The main focus will be on femtosecond laser micromachining in transparent materials (typically glasses and crystals) where nonlinear absorption of light results in strongly localized permanent modifications of the material itself. At lower laser fluence “gentle” modifications can be induced, allowing direct writing of high quality optical waveguides. Waveguides characteristics can be optimized to make them suitable for the realization of integrated quantum circuits. At higher laser fluence nanogratings can be formed inside the material that allow selective chemical etching of microchannels. By combining waveguides and microchannels fully‐integrated micro‐optofluidic devices for sensing can be realized. Some typical applications will be presented, with particular focus on quantum technologies, to better illustrate the versatility and peculiarities of the technique. The results obtained show the strong potential of this microfabrication technology, paving the way to increasingly compact and multifunctional integrated quantum photonic and microfluidic devices.

Arno Rauschenbeutel
Chiral quantum optics
A. Rauschenbeutel, Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Austria
Tightly confined light fields exhibit an inherent link between their local polarization and their propagation direction. The interaction of such spin-momentum-coupled light with quantum emitters therefore features chiral, i.e., propagation-direction-dependent, effects. This chiral light-matter interaction is not accounted for in standard quantum optics and offers fundamentally new functionalities and applications in quantum photonics.

Anna Maria Sitek
Controlled Coulomb effects in core-shell quantum rings
A. Sitek1,2, M. Urbaneja Torres1, K. Torfason1, V. Gudmundsson3, and A. Manolescu1
1School of Science and Engineering, Reykjavik University, Iceland
2Department of Theoretical Physics, Wroclaw University of Science and Technology, Poland
3Science Institute, University of Iceland, Reykjavik, Iceland

We analyse theoretically the possibilities of contactless control of in-gap states formed by a pair of electrons confined in a triangular quantum ring. The in-gap states are corner-localized states associated with two electrons occupying the same corner area, and thus shifted to much higher energies than other corner states, but still they are below the energies of corner-side-localized states. We show how the energies, degeneracy and splittings between consecutive levels change with the orientation of an external electric field relatively to the polygonal cross section. We also show how absorption changes in the presence of external electric and magnetic fields.

Jürgen Volz
Quantum optical circulator controlled by a single chirally coupled atom
J. Volz, M. Scheucher, A. Hilico, E. Will, and A. Rauschenbeutel
Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Austria

Here we demonstrate the experimental realization of a fiber-integrated optical circulator whose operation direction is controlled by the quantum state of a single atom. The device is based on a bottle whispering-gallery-mode microresonator interfaced by two optical nanofibers. Depending on its internal state, the single atom couples differently to the chiral resonator fields. This results in a direction dependent transmission through the resonator and thus realizes an optical circulator. The demonstrated quantum optical circulator opens new ways for routing and processing quantum information in optical circuits.

RONEXT invited presentations:

Andrea Fumagalli
Orchestration of reliable three-layer networks
Zhen Lu1, A. Shakeri1, M. Razo1, M. Tacca1, A. Fumagalli1, G.M. Galimberti2, G. Martinelli2, and G. Swallow2
1Open Networking Advanced Research (OpNeAR) Lab, UT Dallas, USA
2Cisco Photonics, Vimercate, Italy

In Wavelength Division Multiplexing (WDM) backbone networks, even a single network element failure can cause significant traffic losses due to the disruption of many active data flows. Protection schemes are widely adopted to mitigate the adverse effect brought in by such devastating failures. Particularly challenging is the application of protection schemes to multi-layer networks. In multi-layer networks, upper layers’ data flows and circuits depend on the availability of lower layers’ circuits, thus creating strong interdependency. For example, when fulfilling constraints imposed by Shared-Risk Link Groups (SRLGs), the number of viable working and protection routing solutions is significantly restricted. In some cases, these routing restrictions may severely limit the overall network throughput and performance. In this study, the authors address this challenge in a three-layer network architecture and describe a procedure that is suitable for implementation in multi-layer network orchestrators.

Marija Furdek
Assessing the effects of physical layer attacks on content accessibility and latency in optical CDNs
C. Natalino1, A. Yayimli2, L. Wosinska1, and M. Furdek1
1KTH Royal Institute of Technology, Stockholm, Sweden
2Istanbul Technical University, Istanbul, Turkey

In content distribution networks, content replicas are geographically distributed over multiple locations to increase reliability and decrease communication latency. The paper investigates the consequences of optical link cuts to the accessibility of content and communication latency for different content placements. These effects are evaluated in terms of average content accessibility for a multitude of scenarios, allowing for the assessment of the criticality of different link cuts, and revealing the worst and the best replica placement practices.

Barbara Martini
Network orchestration in reliable 5G/NFV/SDN infrastructures
B. Martini1, M. Gharbaoui2, S. Fichera2, and P. Castoldi2
1National Inter-University Consortium for Telecommunications (CNIT), Pisa, Italy
2Scuola Superiore Sant’Anna, Pisa, Italy

In this paper, we elaborate an SDN orchestration solution aiming at the dynamic adaptation of service chain paths thereby addressing high-availability requirements of 5G applications. We present an SDN orchestrator that periodically monitors the availability of the network and, if necessary, promptly adapts service chain paths to recover from congestion events and to preserve network QoS performance of service data flows. A set of performance results are finally presented.

Jacek Rak
Disciplines and measures of information resilience (COST CA15127-RECODIS paper)
J. Rak1, M. Jonsson2, D. Hutchison3, and J.P.G. Sterbenz3,4,5
Gdansk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Poland
2Halmstad University, Centre for Research on Embedded Systems (CERES), Sweden
3Lancaster University, School of Computing and Communications, UK
4The University of Kansas, EECS and Information & Telecommunication Technology Center, USA
5Department of Computing, Hong Kong Polytechnic University, Kowloon, Hong Kong

Communication networks have become a fundamental part of many critical infrastructures, playing an important role in information delivery in various failure scenarios triggered e.g., by forces of nature (including earthquakes, tornados, fires, etc.), technology-related disasters (for instance due to power blackout), or malicious human activities. A number of recovery schemes have been defined in the context of network resilience (with the primary focus on communication possibility in failure scenarios including access to a particular host, or information exchange between a certain pair of end nodes). However, because end-users are becoming more and more interested in information itself (regardless of its physical location in the network), it is appropriate to complement the well-defined framework of network resilience with one that addresses information resilience, and to introduce definitions of relevant disciplines and measures, as proposed in this paper.

Nina Skorin-Kapov
Survivable manycast, anycast and replica placement in optical inter-datacenter networks
M. Furdek, A. Muhammad, and N. Skorin-Kapov
Centro Universitario de la Defensa (CUD), Base Aérea de San Javier, Santiago de la Ribera, Spain

Inter-datacenter networks need to support datacenter communication with the end-users, as well as content replication and synchronization between datacenters. This paper presents a survivable manycast, anycast and replica placement strategy for optical inter-datacenter networks resulting in reduced overall network resource consumption.

Marco Tacca
Demonstration of an SDN orchestrator for both flow provisioning and fault handling in an Ethernet-over-WDM network
B. Mirkhanzadeh1, Chencheng Shao1, M. Razo1, M. Tacca1, A. Fumagalli1, M. Cardani2, G.M. Galimberti2, and G. Martinelli2
1Open Networking Advanced Research (OpNeAR) Lab, UT Dallas, USA
2Cisco Photonic, Vimercate, Italy

In this work we demonstrate a Software Defined Networking (SDN) Orchestrator that is able to provide two critical functions in an Ethernet-over-Wavelength Division Multiplexing (WDM) network. The two functions are flow provisioning at the Ethernet layer and coordinated fault-handling at both Ethernet and WDM layer. With the former function, the Orchestrator can self-provision disjoint optical circuits to fulfill the Ethernet flow fault-tolerant requirements while at the same time minimizing the number of flow rules that are required in the Ethernet switches. With the latter function, the Orchestrator instructs the WDM layer to restore the optical circuits disrupted by a single fiber fault, thus timely returning the Ethernet flows to their pre-fault original configuration.

Luca Valcarenghi
Virtualized eNB latency limits
L. Valcarenghi, F. Giannone, D. Manicone, and P. Castoldi
Scuola Superiore Sant’Anna, Pisa, Italy

In flexible functional split, functions of a virtualized eNB can be disaggregated in distributed computational resources.  One of the main constraints for their placement is the latency experienced by the communication between the VM hosting the functions. This paper evaluates experimentally the latency limits for different functional splits providing insight on flexible functional split implementation.

Xuelin Yang
Security and performance improvement in OFDM transmission using chaotic precoding
Xuelin Yang, Adnan Hajomer, Zanwei Shen, and Weisheng Hu
State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, China

We propose and demonstrate signal encryption schemes using digital chaos for orthogonal frequency division multiplexing (OFDM) signals, where discrete Fourier transform (DFT) and Walsh-Hadamard transform (WHT) are applied as chaotic precoder for peak-to-average power ratio (PAPR) reduction. The physical-layer security during transmission is enhanced, where a huge key space is created by digital chaos. Moreover, the OFDM transmission performance is jointly improved due to the effective PAPR reduction benefited from pseudo-random properties of digital chaos.

SWP invited presentations:

Pierre-Michel Adam
Quantum emitters, nanoantennas and plasmonics
P-M. Adam, Laboratoire de Nanotechnologie et d’Instrumentation Optique, Université de Technologie de Troyes, France
Plasmonics is a now well-established field finding numerous applications in pharmacology, biology, optoelectronics and metamaterials among others. For the sensitive detection of molecules or markers Surface Enhanced Spectroscopies, such as Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Fluorescence (SEF), are widespread and the most used for applications. Both these enhanced spectroscopies rely on local field enhancements in the near vicinity of resonant metallic nanoparticles when Surface Plasmon oscillations are driven for a specific optical wavelength. SERS can achieve single molecule detection when two or more metallic nanoparticles are coupled through their near-fields, resulting in enhancements usually ranging from 4 up to 10 orders of magnitude, even if the way to evaluate such an absolute magnitude of enhancement is still a subject of debate. A drawback is that these highly sensitive SERS substrates are difficult to reproduce and control. Less enhancement is obtained with SEF but usually the intrinsic fluorescence cross section of a molecule is more than 10 orders of magnitude more important than that of its non-resonant Raman cross-section. In SEF one has to take into account the finite lifetime of the excited levels of the molecule of interest, which results in quantum yield modifications in the presence of the metallic nanoparticles. Quantum yield can be enhanced or even reduced, leading in the latter case to a competition with local field excitation enhancement and thus the possibility of quenched fluorescence from the emitters. This contribution will show our recent progress towards the understanding of SERS and SEF effects on a variety of coupled nanosystems [M. Yehia Khaywah, et al., Ultra stable, uniform, reproducible and highly sensitive random arrays of bimetallic nanoparticles as reliable large scale SERS substrates, The Journal of Physical Chemistry C., 119 (46), 26091–26100, 2015], [A. Muravitskaya, et al., Enhanced Raman scattering of ZnO nanocrystals in the vicinity of gold and silver nanostructured surfaces, Optics Express, 24 (2), A168-A173, 2016], [S. Ashraf et al., Effects of irregular Bi-metallic nanostructures on fluorescence emission of Photosystem I from Thermosynechococcus elongatus, Photonics, 2, 838-854, 2015].

Hovik Baghdasaryan
Solution of boundary problems in intensity-dependent nano-optics and quantum mechanics by the method of single expression
H.V. Baghdasaryan1, T.M. Knyazyan1, T.T. Hovhannisyan1, M. Marciniak2
1National Polytechnic University of Armenia, Yerevan, Armenia
2National Institute of Telecommunications, Warsaw, Poland

For boundary problems solution in optics and quantum mechanics the same methods are in use. However, with the increase of local light intensity in nano-optics and energy of particles in quantum mechanics nonlinear phenomena are appeared and, as a consequence, new approach for boundary problems solution is topical. Non-traditional Method of Single Expression (MSE) is an alternative approach permitting to obtain steady-state solution of boundary problems at any value of intensity-dependent nonlinearity. Previously the MSE has been successfully used in wavelength-scale optics of multilayer and modulated structures. In the present work in parallel to the nano-optics the MSE’s application in quantum mechanics is considered. The similarities and differences in application of the MSE in these two areas are discussed.

Jean-Michel Benoit
Coherence in disordered emitters coupled to surface and long-range plasmons
J.M. Benoit, K. Chevrier, C. Symonds, J. Paparone, and J. Bellessa
Institut Lumière Matière, Université Claude Bernard Lyon 1, Villeurbanne, France

In this work, we will present our on-going research on strong coupling between plasmons and molecular emitters. Localized and delocalized plasmons in metallic nanoparticles are associated with a strongly confined electromagnetic field, inducing an enhanced interaction with emitters located close to the metal. When the plasmon/emitter interaction overtakes the damping in the system, the system enters into strong coupling regime leading to light-matter hybridization. If we take into account the microscopic structure of the molecular film, collective effects between the delocalized plasmon and the set of molecules occurs. The excitations are not localized in a single particle anymore but delocalized on a large number of particles due to the formation of an extended hybridized state over several microns which modify various properties of molecular materials like conductivity or reactivity. However, the extension of the coherent state is limited by the reduced plasmon propagation length, due to metal losses. We will show that the coherence length can be extended using a low loss surface plasmon in a symmetrical structure. After the demonstration of strong coupling between aggregated dyes and long range plasmon, we will evaluate the extension of the coherent polaritonic mode in the structures. A coherence length up to several tens of microns can be achieved.

Muriel Botey
Polarization-independent broadband bidirectional optical cloaking using a new type of inverse scattering approach
Z. Hayran, R. Herrero, M. Botey, H. Kurt, and K. Staliunas
Escola Universitària d’Enginyeria Tècnica Industrial de Barcelona, Consorci Escola Industrial de Barcelona, Spain

Since the advent of transformation optics a decade ago, the ability to achieve optical cloaking has become a matter of practical realization. However, so far extreme material requirements and large device areas have significantly posed an obstacle to realize compact cloaking schemes that are fully functional. Here, by taking a different approach and by following our recently developed general theorem to control the scattering behaviour of an arbitrary object on a specific demand, we show that nearly perfect bidirectional optical cloaking effect can be generated for any type of object with a given shape and size. Contrary to previous approaches, we reveal that such a method is always able to produce local refractive indices larger than one and that neither gain nor lossy materials are required. Furthermore, by means of numerical calculations, we demonstrate a highly tunable broad operational bandwidth of 550 nm (covering 650 –1200 nm interval) and an angular aperture of 36° for both directions and polarizations. With these unprecedented features, we expect that the present work will hold a great potential to enable a new class of optical cloaking structures that will find applications particularly in communication systems, defence industry and in other related fields.

Georges Boudebs
Nonlinear properties of unfilled d shell metal porphyrins using the beam waist relative variation method
G. Boudebs, M. Chniti, C. Cassagne, and Hongzhen Wang
LUNAM Université, Université d’Angers, LPhiA, Laboratoire de Photoniques d’Angers, EA 4464, Université d’Angers, France

We study the nonlinear absorption and refraction of 5,10,15,20-tetraphenyl-21H,23H-porphin cobalt(II) (CoTPP) and 5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphin cobalt(II) (MCoTPP). The measurements were carried out in solutions prepared in chlorobenzene applying the D4σ-Z-scan technique with a laser delivering single pulses in the picosecond regime at 532 nm. For each compounds, the NL coefficients were measured for three concentrations. The results show that these materials with unfilled d shell exhibit a saturable absorption (SA), where they have been compared to the basic structure tetraphenylporphyrin TPP and zinc tetraphenylporphyrin ZnTPP with filled d shell metal in order to see the influence of the central metal ion on the nonlinear absorption behavior.

Louise Bradley
Influence of plasmonic array geometry on non-radiative energy transfer from a quantum well to a quantum dot layer
L.J. Higgins1, C.A. Marocico1, J. Garcia Coindreau1, V.D. Karanikolas1, A.P. Bell1, J.J. Gough1, G.P. Murphy1, P.J. Parbrook2, and A.L. Bradley1
School of Physics and CRANN, Trinity College Dublin, Ireland
2Tyndall national Institute and School of Engineering, University College Cork, Ireland
The influence of ordered plasmonic arrays on energy transfer from a quantum well to a quantum dot layer has been investigated. The ordered arrays are comprised of nanostructures of different geometries, including boxes, disks and rings. Despite no signature of non-radiative energy transfer in the absence of an array, an efficiency of ~51% is observed for a ring array, though strong emission quenching yields an overall increase of only ~ 14% of the QD emission. The QD emission is enhanced by ~25% for disk arrays, and was found to be relatively insensitive to the gap between disks. In contrast, the QD emission enhancement decreases from ~70% to 40% as the separation between boxes increases from 100 nm to 160 nm. The largest increase in QD emission of ~70% is due to a non-radiative energy transfer efficiency of ~25% coupled with a QD emission enhancement factor of ~1.4. The results demonstrate the flexibility offered by plasmonic arrays to optimise non-radiative energy transfer or to benefit from a combination of energy transfer and enhanced radiative emission, relevant to sensing and colour conversion applications.

Pavel Cheben
Recent advances in on-chip Fourier transform spectrometers
P. Cheben1, H. Podmore2, A. Herrero3,4, A.V. Velasco3, J.H. Schmid1, A. Scott5, M. Vachon1, R. Lee2, M. L. Calvo4, D.X. Xu1, S. Janz1, and P. Corredera3
1National Research Council, Information and Communications Technologies, Ottawa, Canada
2Department of Physics and Astronomy, York University, Toronto, Canada
3Consejo Superior de Investigaciones Cientificas, Madrid, Spain
4Universidad Complutense de Madrid, Spain, 5Honeywell Aerospace, Kanata, Canada

We report our advances in development of on-chip Fourier-transform spectrometers. Specifically, we present applications of subwavelength engineered waveguides in a new type of a compressive-sensing Fourier-transform spatial heterodyne spectrometer chip. The spectrometer is implemented as an array of Mach-Zehnder interferometers (MZIs) integrated on a photonic chip. The signal from a set of MZIs comprises an undersampled discrete Fourier interferogram, which is inverted using L1-norm minimization technique to retrieve a sparse input spectrum. To implement this technique we use a subwavelength-engineered spatial heterodyne Fourier-transform spectrometer on a chip comprising 32 independent MZIs.  We demonstrate the retrieval of three sparse input signals by collecting data from restricted sets (8 and 14) of MZIs and applying common compressive-sensing reconstruction techniques to this data. We show that this retrieval maintains the full resolution and bandwidth of the original device despite a sampling factor as low as 1/4th of a conventional (non-compressive) design. We successfully demonstrate the retrieval of various sparse input signals by collecting data from a truncated interferometer array and show that the spectral retrieval maintains the full resolution and bandwidth of the original device despite a sampling factor as low as 1/4th that of conventional designs. Furthermore, we present two techniques for mitigating and correcting the effects of temperature drifts in waveguide spatial heterodyne Fourier-transform on-chip spectrometers. In high-resolution devices, waveguide length and thermal dependence lead to a sensitivity to environmental variations and impose strict conditions on the thermal stabilization system, ultimately limiting device operation. In order to overcome this limitation, two novel temperature mitigation techniques based on a temperature-sensitive calibration and phase errors correction are demonstrated experimentally. The spectrometer under analysis comprises an array of 32 Mach-Zehnder interferometers fabricated on a silicon-on-insulator platform. with microphotonic spirals of linearly increasing length up to 3.779 cm, yielding  a spectral resolution of 17 pm. We demonstrate the elimination of the degradation in retrieved spectra caused by temperature drifts.

Caterina Ciminelli
Photonic, plasmonic and hybrid nanotweezers for single nanoparticle trapping and manipulation
C. Ciminelli, D. Conteduca, F. Dell’Olio, G. Brunetti, T.F. Krauss, and M.N. Armenise
Optoelectronics Laboratory, Politecnico di Bari, Italy

Trapping and manipulation of matter at micrometer scaled up to a single nanoparticle has assumed a fundamental role for several applications and, particularly, in biomedical environments. Furthermore, trapping of living matter at the nanoscale, such as proteins and DNA sections, allows the study of many diseases and also the investigation of the effects of new drugs on a single pathogen like a virus.  Among the several trapping techniques proposed to control the motion of sub-micrometer particles, optically-based methods have demonstrated the highest efficiency. Strong optical forces obtained with low values of optical power and a contact-free manipulation represent the main advantages of optical tweezers, because long trapping time with no risks of damage of the trapped matter can be realized. Integrated optical nanotweezers provide stronger optical forces with a higher trapping efficiency, compared to performance obtained with bulk configurations.  In this work, we review the state-of-the-art of nanotweezers proposed for trapping at sub-micrometer and nanoscale. Performance obtained with photonic and plasmonic nanotweezers are discussed, with a special emphasis on the hybrid photonic/plasmonic nanodevices that allow very strong light-matter interaction (Q/V > 106 (λ/n)-3) with clear advantages for trapping efficiency at the nanoscale.

Mária Csete
Plasmonic structure integrated superconducting nanowire single-photon detectors optimized for quantum information processing applications
M. Csete, A. Szenes, D. Maráczi, B. Bánhelyi, T. Csendes, and G. Szabó
Department of Optics and Quantum Electronics, SZTE University, Szeged, Hungary

Optimization of superconducting nanowire single photon detectors (SNSPD) consisting of four types of integrated plasmonic structures was performed to maximize the absorptance (A-SNSPD), as well as the polarization contrast with (C-SNSPD) and without (P-SNSPD) a criterion regarding the absorptance that have to be parallel met. The optimal configurations of all A-SNSPDs correspond to a device design and periodicity dependent tilting in S-orientation (90° azimuthal angle), however the polarization contrast is moderate. In C-SNSPDs correlation between the polarization contrast and the NbN/Au volume fraction ratio as well as the normalized cavity length parameters was shown. In P-SNSPD configurations capable of maximizing the polarization contrast the high p-polarized absorptance is achieved at the plasmonic Brewster angle, which is inside the region of suppressed s-polarized absorptance.

Richard De La Rue
Array metasurfaces for biomedical sensing at infra-red wavelengths
R.M. De La Rue1, I.G. Mbomson1, J. Paul1, S. Tabor1, B. Lahiri1, G.J. Sharp1, H. Vilhena2, S.G. McMeekin2, and N.P. Johnson1
1Optoelectronics Research Group, School of Engineering, University of Glasgow, UK
2School of Engineering and Built Environment, Glasgow Caledonian University, UK
Detection and identification of biomedically significant molecules is an important application in infra-red (IR) spectroscopy. This presentation will consider some of the significant features of the different alternative building-block elements that can be used in array metasurfaces for enhanced detection sensitivity. The presentation will also address techniques and issues associated with the deposition and localisation of biological and organic chemical molecular material for detection and measurement using IR spectroscopy.

Aloyse Degiron
Artificial media for optoelectronics
Q. Le-Van, H. Wang, X. Le Roux, A. Aassime, and A. Degiron
Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Orsay, France

We will show that colloidal quantum dots coupled with gold nano-antennas can form the basis of a new form of artificial medium for optoelectronics. We will demonstrate these ideas by introducing the concept of structural electroluminescence (arising from geometrical effects in discrete blocks of subwavelength dimensions) and discuss the potential of these findings for LEDs, displays, light-harvesting devices and sensors.

Wolfgang Elsäßer
Two novel experimental schemes for terahertz tomography
T. Mohr and W. Elsäßer
Institute of Applied Physics, Technische Universität Darmstadt, Germany

In this contribution, we demonstrate two novel and compact terahertz tomography spectroscopy concepts. First, we exploit continuous-wave (CW) terahertz radiation generation and phase-sensitive detection in the same single photoconductive antenna (PCA), a homodyne self-mixing detection approach and apply it within a 2D terahertz tomography imaging application where we reconstruct the two-dimensional image of a hollow-core Teflon cylinder filled with α–lactose as a proof-of-concept demonstration. Second, we realize a single-pixel tomography scheme where 2D tomographic spatial information is achieved by spatially-resolved photodoping of a high-resistivity silicon wafer plate giving rise to fast transverse single-pixel information (via a digital micro mirror device (DMD)) with the subsequent rotation of the object for tomography. Both concepts offer a significantly reduced complexity and consequently lower cost of the terahertz spectroscopy setup and their THz performance will be discussed and compared.

Didier Felbacq
Dyakonov-Shur instability for terahertz electromagnetic radiation generation
M.R. Razafindrakoto, F. Bigourdan, and D. Felbacq
Université Montpellier, France

Two decades ago, M. Dyakonov and M. Shur predicted the emission of THz electromagnetic (EM) radiation by simple transistors. Their mechanism showed great potential as it uses a cheap to build and compact device. When submitted to a constant source-to-drain current and a constant gate-to-source voltage, hydrodynamical instabilities in small enough transistors should induce a spontaneous oscillation of the electron density field (plasma wave) inside their channels. The criteria for such instability are refined as compared to the original predictions in this paper. The extraction of independent constant is given allowing experimental verification. The more constraining conditions may explain the difficult observation of Dyakonov-Shur instabilities in experimental studies.

Martin Ferus
Recording and evaluation of high resolution optical meteor spectra and comparative laboratory measurements using laser ablation of solid meteorite specimens
M. Ferus1, J. Koukal2, L. Lenža2, J. Srba2, P. Kubelík1,3, V. Laitl1,2, E.M. Zanozina1,3, P. Váňa1, T. Kaiserová1, A. Knížek1, and S. Civiš1
1J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
2Valašské Meziříčí Observatory, Valašské Meziříčí, Czech Republic
3Institute of Physics, Czech Academy of Sciences, Praha, Czech Republic
Important features in meteor spectra are usually interpreted by synthetic convolution of lines extracted from databases. For such an assignment, in our study, we employed experimental technique of meteorite specimen laser ablation spectroscopy. The spectra are recorded by high resolution laboratory Echelle spectrograph and simultaneously using novel high resolution Meteor Spectral Camera for meteor observation. The data are subsequently evaluated via calibration-free method alongside with analysis of real meteor emission spectra. Additionally, spectral features related to airglow plasma are compared with the spectra of the Laser Induced Breakdown in the air. In this manner, we show that instead of theoretical spectra simulation, laboratory experiments can be applied in evaluation of the observational data.

Stavroula Foteinopoulou
Perfectly asymmetric reflection enables unidirectional emission in a phonon‑polariton (reststrahlen-band) material platform
S. Foteinopoulou1 and G.C.R. Devarapu2
1Center for High Technology Material (CHTM), Univ. of New Mexico, Albuquerque, NM, USA
2Cork Institute of Technology (CIT), Cork, Ireland
Highly asymmetric effects in the photonic responses of structured materials have been attracting increasing attention recently, since they enable a higher degree of directional diversion of light that is conducive to application specific demands. We explore here a particular type of an asymmetric photonic response that is related to the system’s reflectance profile. We show that the asymmetric reflectance profile of a photonic system can be tuned with an appropriate synergistic control of the geometric-structure asymmetry and the intrinsic material dissipation. Even extreme, near-perfect reflector materials can be sculpted so that reflection is almost totally suppressed for light incident from one-side while the structure maintains the near-perfect reflector property for light incident from the other side. We demonstrate this effect with a platform comprising a phonon-polariton material, in particular SiC, which in bulk form repels light within the reststrahlen-band spectrum.  We subsequently explain, how as a consequence of Kirchhoff’s law, the aforementioned asymmetric reflection response enables such platform to operate as a near-unidirectional emitter. We believe that these results are important for highly efficient one-way THz/infrared sources as well as passive radiative cooling devices.

Wolfgang Freude
PIPED: A silicon-plasmonic high-speed photodetector
W. Freude1, S. Muehlbrandt1,2, T. Harter1,2, A. Melikyan1,2,5, K. Köhnle1,2, A. Muslija2, P. Vincze3, S. Wolf1, P. Jakobs2, Y. Fedoryshyn6, J. Leuthold6, M. Kohl2, T. Zwick4, S. Randel1, and C. Koos1,2
1Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), Germany
2Institute of Microstructure Technology (IMT), KIT, Germany
3Institute of Nanotechnology (INT), KIT, Germany
4Institute of Radio Frequency Engineering (IHE), KIT, Germany
5Now with NOKIA – Bell Labs, Holmdel, USA
6Institute of Electromagnetic Fields (IEF), ETH Zurich, Switzerland

Silicon-plasmonic photodetection based on internal photoemission exploits the intrinsic absorption in plasmonic waveguides at metal-dielectric interfaces. For this purpose we designed an asymmetric metal-semiconductor-metal waveguide with a width of 75 nm. Our plasmonic internal photoemission detector (PIPED) shows a record-high photocurrent sensitivity of up to S = 0.12 A/W for light at a wavelength of 1550 nm. The opto-electronic bandwidth is extremely large and allows data reception at rates of at least 40 Gbit/s. As another application, photomixing of two different optical carriers incident on the PIPED generates photocurrents with THz-frequencies, which can be used for short-range wireless communication. Finally, because in contrast to ordinary pin-photodetectors the sensitivity S(U) depends on the voltage U across the device, a PIPED can be employed for all-optical heterodyne reception and down-conversion of data on a THz carrier.

Konstantin Gaikovich
Methods of near-field subsurface diagnostics: Theory, study, comparison
K.P. Gaikovich, Institute for Physics of Microstructures RAS, Nizhniy Novgorod, Russia
Methods of electromagnetic near-field diagnostics of subsurface dielectric inhomogeneities are presented. This diagnostics includes tomography of 3D distributed inhomogeneities 3D of complex dielectric permittivity, holography (shape reconstruction) of solid targets and profiling (retrieval of depth profiles) of one-dimensional inhomogeneities. Methods are based on the solution of inverse scattering problems by data of electromagnetic near-field measurements with electrically-small probes that provide a subwavelength resolution. For that, various algorithms have been applied to solve corresponding nonlinear ill-posed problems (Tikhonov’s and dual regularization). In these algorithms, various measuring schemes (point or 2D scanning) and input data (pulse, multifrequency, multilevel, impedance) have been in use. Results of theoretical and experimental studies of their efficiency are demonstrated.

Sonia García-Blanco
Towards an active biosensing platform in rare-earth ion doped Al2O3 microring resonators
M. de Goede, M. Dijkstra, and S.M. García-Blanco
Optical Sciences Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands

Waveguide microring resonators sensors are numerously found in the Si-based technologies. Their operation, however, requires the operation of a tunable laser and the real-time monitoring of the location of their resonance peaks. An active material with gain could omit such operation through the detection of a laser-generated signal. Here, Al2O3 is presented as an alternative technology that has the potential for such active sensing applications. Microring resonators of undoped and Er3+-doped Al2O3 were fabricated and characterized. The undoped microring resonator was used for bulk refractive index sensing with a highest sensitivity of 95 nm/RIU and a limit of detection of 2.5e-6 RIU. After optical pumping the doped devices experienced the compensation of loss through internal gain, but the losses were too high to achieve lasing in the device. This work shows the feasibility of realizing passive sensors on the Al2O3 platform and efforts are ongoing to transcend the platform from a passive to an active operation.

Olivier Gauthier-Lafaye
1D crossed gratings for narrow band polarization insensitive reflective filtering
K. Sharshavina1, S. Pelloquin1, E. Daran1, J.B. Doucet1, F. Lemarchand1, T. Bégou1, J. Lumeau1, A. Monmayrant1, P. Arguel1, O. Gauthier-Lafaye1, E. Popov2, and A.L Fehrembach2
LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
2Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, France

We present experimental characterizations of 1D crossed Guided Mode Resonant Filters (GMRFs) in the near infrared fabricated by nanoimprint lithography. We will show that subwavelength gratings up to 4'' diameter can be fabricated using such techniques. We compare the performances of the GMRFs to the performances of Fabry-Perot filters and discuss the sensitivity to fabrication inhomogeneity of these components.

Igor Goncharenko
Electric field sensor on the base of horizontal and vertical slot waveguide ring microresonators with LC filling
I.A. Goncharenko1, M. Marciniak2, and V.N. Reabtsev1
1Institute for Command Engineers, Minsk, Belarus
2National Institute of Telecommunications, Warsaw, Poland

We consider the operation principles of the sensor of an external electric field on the base of the microring resonators that consist of the bent strip waveguides with vertical or horizontal slots filled with nematic LC. The mode field distribution and dispersion parameters of the bent slot waveguides are calculated by using the algorithm based on the Method of Line. The influence of the waveguide and microresonator structure (slot width, position and orientation, microresonator radius, etc.) on the sensor sensitivity is analyzed.

Cristiana Grigorescu
New advances in analytic and diagnostic technologies based on Raman spectroscopy
L.O. Scoicaru1, M.I. Rusu1, C.R. Iordanescu (Stefan)1, B. Chiricuta2, M.V. Udrea2, R. Munteanu3, I.A. Birtoiu3, C. Rizea4, and C.E.A. Grigorescu1
1National Institute of Research and Development for Optoelectronics INOE 2000, Magurele, Romania
2Apel Laser S.R.L, Bucharest, Romania
3Faculty of Veterinary Medicine-University of Agronomic Sciences and Veterinary Medicine, Bucharest, Romania
4Roxy Veterinary S.R.L. Magurele, Romania

The progress of a method employed in a particular field should be considered for both knowledge and technological advances while equipment grows along with specific challenges. In this context we present our most recent results in using surface enhanced Raman scattering (SERS) as a real time diagnostic means in veterinary oncologic surgery. The in-house built portable Raman spectrometer is based on fibre optics technology and employs visible excitation light. A model for a diagnostic sequence based on principal component analysis is also presented.

Brana Jelenković
Optical properties of volume gratings with nanosphere-filled layers – Biomimetics of moth structures
S. Savić-Šević1, B. Salatić1, D. Pantelić1, B. Jelenković1, S. Čurčić2, and D. Stojanović3
1Institute of Physics, University of Belgrade, Serbia
2Institute of Zoology, University of Belgrade, Serbia
3Institute of Lowland Forestry and Environment, University of Novi Sad, Serbia
A new type of layered photonic structure, whose alternating layers are filled with randomly dispersed nano-spheres, is fabricated and  its optical properties are experimentally and theoretically analysed. Structures are made on a pullulan doped with chromium ions (dichromated pullulan – DCP) using holography.  We found that experimental structures are similar to those observed on wings of the Diachrysia chrysitis moth, having layers of overlapping scales. DCP photonic structure has alternating air-pullulan layers, held in place by sparsely separated nano-pillars, and air voids filled with 30-60 nm diameter nanospheres which act as scatterers. Theoretical analysis of such structures shows that the scattering and interference interact to enhance the local field within the layers and increase the residual absorption of the material. We compare optical properties of moth scales with properties of structures fabricated in DCP, and calculated from the functional model.

Animesh Jha
Near-IR mode-locked laser assisted sintering and morphological engineering of biomaterials – A new approach for integrative manufacturing of hard-soft tissues for in-theatre use!
A. Anastasiou1, T. Edwards2, J.G. Addis1, C. Thompson2, C. Amorese3, R. Ireson4, S. Strafford5, M. Malinowski5, M.N. Routledge6, A. Brown1, N. Hondow1, J. Bain6, T. Brown2, Z. Kalmej1, M. Petruzzi7, R. Grassi7, M.S. Duggal5, P.V. Giannoudis8, and A. Jha1
1School of Chemical & Process Engineering, University of Leeds, UK
2School of Physics & Astronomy, University of St Andrews, UK
3ICMEA SRL, Corato (Bari), Italy
4Glass Technology Services, Sheffield, UK
5School of Dentistry, University of Leeds, UK
6M Squared Lasers, Glasgow, UK
7Dipartimento Interdisciplinare di Medicina, Università degli Studi di Bari, Italy
8Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK

The emergence of mode-locked near-IR (NIR) lasers has opened novel and exciting opportunities in dental and orthopaedic medicine. In a mode-locked laser cavity the pulse duration and repetition rates may be controlled between 10-100s of femtosecond (fs) and kHz-GHz ranges, respectively. This unique capability for controlling the incident laser power in a near-IR mode-locked laser has been explored for studying the materials phase transformation, sintering and bonding mechanisms in calcium phosphate and chitosan/calcium phosphate suspensions as biomaterials. The investigation primarily focusses on interaction of such a laser in a linear regime, resulting in a plethora of phase combinations and morphologically controlled structures, which are well suited for in-theatre processing of hard-soft tissues for personalized therapy. In this article, the engineered medical device which combines the materials and laser power delivery at the point of tissue restoration is also discussed. The article exemplifies the case for enamel restoration using such a medical device, which then sets the scene for much wider use in tissue engineering.

Vladimír Kuzmiak
Edge states in periodically modulated finite PT-chain and photonics slabs consisting of dielectric cylinders
V. Kuzmiak1 and P. Markoš2
1Institute of Photonics & Electronics, Czech Academy of Sciences, Praha, Czech Republic
2Department of Experimental Physics, Faculty of Mathematics Physics and Informatics, Comenius University in Bratislava, Slovakia

We study both frequency and transmission spectrum of finite 1D and 2D array of the dielectric cylinders. In particular we are interested in the spectral properties of a finite one-dimensional chain of the dielectric cylinders with periodically modulated refractive index which satisfies the condition of PT symmetry which resembles the system considered recently by Phang et al. [Sci. Reports 6, 2045 (2016)].  We show that the frequency spectrum of such system consists of the discrete modes which can be taken as translational invariant and the edge modes where the translational symmetry is broken.  We discuss the properties of the edge modes for different types of the modulation and the differences between the edge modes in PT and non-PT symmetric systems observed recently.

Andrei Lavrinenko
Non-diffractive tractor beams
A. Novitsky1,2, Dongliang Gao3, A.A. Gorlach2, Cheng-Wei Qiu4, and A.V. Lavrinenko1
1Department of Photonics Engineering, Technical University of Denmark, Copenhagen, Denmark
2Department of Theoretical Physics and Astrophysics, Belarusian State University, Minsk, Belarus
3College of Physics, Optoelectronics and Energy, Soochow University, Suzhou, China
4Department of Electrical and Computer Engineering, National University of Singapore

Pulling optical force discovered recently in the theory and experiment has drawn great attention owing to its counterintuitive nature and promising applications. Pulling force originates from the enhanced forward light scattering that in accordance with the momentum conservation conveys light momentum to particles in the backward direction. The amplified forward scattering is achieved through the interaction of multipoles, conventionally electric and magnetic dipole moments. In this talk we give an overview of the tractor beams in optics, acoustics, classical and quantum mechanics. We demonstrate how to ease the conditions required in experiment for realization of the optical tractor beams using the cylindrical objects. We pay a particular attention to the case of the pulling optical force due to the interaction of magnetic dipole and quadrupole moments.

Boris Lembrikov
Metal/insulator/metal (MIM) plasmonic waveguide containing a smectic A liquid crystal (SALC) layer
B.I. Lembrikov, D. Ianetz, and Y. Ben-Ezra
Department of Electrical Engineering, Holon Institute of Technology, Israel

Different types of plasmonic waveguides have been recently proposed such as metal nanoparticle chains, metal films, metal/insulator/ metal (MIM) slabs, metal strips, etc. We have shown recently that the nonlinear optical phenomena are strongly pronounced at the interface of a metal and a smectic A liquid crystal (SALC) due to the nonlinear surface plasmon polariton (SPP)  mixing in SALC with a large Kerr nonlinearity. In this paper, we investigated theoretically a MIM waveguide containing a SALC layer. We evaluated the modes of such a MIM waveguide and the nonlinear polarization caused by the smectic layer displacement.

Matthias Lenzner
A Sagnac Fourier spectrometer
M. Lenzner1 and J-C. Diels2
1Lenzner Research LLC, Tucson, USA
2Unversity of New Mexico, Albuquerque, USA

When a transmission grating is placed in a Sagnac interferometer, two diffracted wavefronts propagate in opposite directions and interfere at the output, forming a Fizeau fringe pattern. This interferogram contains spectral information heterodyned around a center wavelength. By changing the design, high resolving power or broad spectral range can be accomplished.

Marco Liscidini
Guided Bloch long-range surface plasmon polaritons
N. Fong1,2, M. Menotti3, E. Lisicka-Skrzek1,2, H. Northfield1,2, A. Olivieri1,2, R.N. Tait4, M. Liscidini3, and P. Berini1,2,5
1School of Electrical Engineering and Computer Science, University of Ottawa, Canada
2Centre for Research in Photonics, University of Ottawa, Canada
3Department of Physics, University of Pavia, Italy
4Department of Electronics, Carleton University, Ottawa, Canada
5Department of Physics, University of Ottawa, Canada

A few years ago, Konopsky showed that a one dimensional photonic crystal structure can be used on one side of a thin metal layer to mimic the optical properties of the material on the other side. Inspired by this approach and motivated by using LRSPP waveguides for biosensing, we propose and realized a thin metal stripe on a truncated  SiO2/Ta2O5 multilayer stack to support a fully guided  LRSPPs. These results further the attraction of metal stripe waveguides and LRSPPs for biosensing applications and more in general for LRSPP integrated optics.

Cefe López
Instances of disorder and its effect in active and passive photonic structures
C. López, Materials Science Factory Unit, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
While disorder has been mostly regarded as a negative factor in technology its underlying scientific aspects have intrigued researchers. Disorder is intrinsic with random lasers and light diffusers, examples of active and passive photonic systems. Progress in controlling its amount, nature and distribution and how light interacts and is affected by it can permit designing better devices and take advantage of bottom up fabrication techniques that have much less restrictive practical requirements. Here I will provide examples of defects percolation, replica symmetry breaking and rough mirror random lasers.

Anatole Lupu
Guided wave metamaterials for integrated optics applications
N. Dubrovina1, Yulong Fan1, X. Leroux1, A. de Lustrac1,2, and A. Lupu1
Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris-Sud, Université Paris-Saclay, France
2Univ. Paris-Ouest, Ville d’Avray, France

This work addresses analysis of hybrid plasmonic/dielectric metamaterials operated in guided wave configurations in the near-infrared domain (λ=1.5µm). The objective is to achieve an efficient control over the flow of the light in the waveguide using effective index variation induced by metasurface resonances. Specifically we consider a composite guiding structure made of a 2D plasmonic metasurface located on the top of high index silicon on insulator waveguide. The great advantages of the considered solution with respect to the conventional multi-layered metamaterials approach are simplified technology and reduced propagation losses. In contrast to photonic crystals approach, the use of plasmonic nanoresonators allows a much higher degree of freedom for the control of effective index.  Depending on the operation with respect to the resonance frequency, effective index either higher or lower as that of the host slab waveguide can be achieved. The considered approach is quite generic and can be adapted to different type of planar lightwave circuits platforms: Silicon, GaN/AlN, InGaAsP/InP, doped silica glass etc. The reported demonstrations opens thus the way to a new family of optical devices based on the use of plasmonic resonances to control the light at nanoscale.

Leonid Mochalov
Thin phase tailoring of As-Te phase change materials
A. Nezhdanov, L. Mochalov, and A. Mashin
Nizhny Novgorod State Technical University, Russia

First time As-Te phase change materials were prepared via plasma-enhanced chemical vapor deposition (PECVD) by low-temperature non-equilibrium plasma at low pressure. RF inductively coupled discharge (40 MHz) was utilized as a plasma source.  Volatile elemental As and Te were the initial substances. Dependence of phase and chemical content of As-Te films on parameters of plasma deposition was studied. Thin phase tailoring of As-Te films was implemented by means of changing of initial substances ratio in gas phase. Phase modification of the films by 632.8 nm laser irradiation was demonstrated.

Mauro Pereira
The linewidth enhancement factor of intersubband lasers
M.F. Pereira, Materials and Engineering Research Institute, Sheffield Hallam University, UK
The linewidth enhancement (α factor)  of intersubband lasers was initially expected to be zero. However, nonzero and even negative values have been found in experiments performed by different teams. This paper resolves this controversy showing that counter rotating terms, usually ignored in simulations are the actual fundamental origin of nonzero α at peak gain even without inclusion of nonparabolicity and many-body effects, which are however needed to explain negative values.  For laser without inversion conditions,  α is found to be larger, but still at the same order of magnitude of conventional inverted medium lasers, thus ensuring their  usefulness for  spectroscopic applications which require sharp laser linewidths [M.F. Pereira, the linewidth enhancement factor of intersubband lasers: From a two-level limit to gain without inversion conditions, Applied Physics Letters 109, 222102 (2016)].

Vincenzo Petruzzelli
Coupling between Si-waveguides and plasmonic antennas for optical networks on chip
G. Calò1, G. Bellanca2, M. Bozzetti1, P. Bassi3, and V. Petruzzelli1
1Dipartimento di Ingegneria Elettrica e dell’Informazione, Politecnico di Bari, Italy
2Department of Engineering, University of Ferrara, Italy
3Department of Electrical, Electronic and Information Engineering ‘Guglielmo Marconi’, University of Bologna, Italy

On-chip wireless optical communications among distant cores in chip multiprocessors can lead to a completely new approach to the limits of current on-chip communication. In fact, using wireless connections mitigates the problems related to the design and the fabrication of hugely complex switching fabrics, where long paths suffer of crosstalk and loss issues. We investigate the possibility of integrating plasmonic nanoantennas and silicon waveguides to allow the compatibility with optical networks and devices. In particular, we report the numerical analysis of a plasmonic Vivaldi antenna coupled to a silicon waveguide. The design criteria and the radiation characteristics are described.

Markus Pollnau
Vacuum fluctuations and the laser linewidth
M. Pollnau, Department of Materials and Nano Physics, School of Information and Communication Technology, KTH-Royal Institute of Technology, Kista, Sweden
The processes of absorption and stimulated emission are investigated via (i) energy conservation in a Fabry-Perot resonator, (ii) the Lorentz-oscillator model, (iii) the Kramers-Kronig relations, and (iv) quantum-optical coherent states as an expansion in Fock space. Vacuum fluctuations are added and the relation between stimulated and spontaneous emission is clarified. It is shown that previous models start from incorrect assumptions about the physical foundations of spontaneous emission. The non-orthogonality of longitudinal optical modes in a linear resonator is investigated and its consequences for the laser linewidth are discussed. Based on these results, a semi-classical approach to the laser linewidth below, around, and above the laser threshold which is consistent with resonator theory is presented. These results also shed new light on the usually considered linewidth-narrowing and -broadening factors.

Pablo Postigo
Low-cost and efficient near-UV grating reflectors for protein detection
E. Baquedano1, R.V. Martinez2, and P.A. Postigo1
1Instituto de Microelectronica de Madrid, CSIC, Madrid, Spain
2School of Industrial Engineering, Purdue University (USA)

Protein detection by optical measurement can be obtained through absorption measurements using wavelengths in the range between 270 and 280 nm. Efficient light sources or optical filters in this wavelength range can avoid the use of spectral measurement for detection [K. Bougot-Robin et al. ,UV imaging of biochips based on resonant grating, Proceedings of SPIE, 7673, art. no. 76730R (2010)]. A study about the relationship between the reflectivity in the near UV and the vertical aspect ratio was performed for gratings fabricated using low-cost soft lithography which allows for easy replication of wide-area nanopatterns [Y. Xia, and G.M. Whitesides, Soft lithography, Annual Review of Materials Science 28,153-84 (1998)]. The reflectivity was measured at 45° in the UV-visible for samples fabricated in silicon and aluminum. A well-defined reflection peak in the range 270-280nm was found in the reflectivity spectrum with features changing depending on the depth of the gratings. Moreover, wetting properties of the gratings were also investigated using contact angle measurements with water droplets, obtaining hydrophobic or hydrophilic gratings depending on the period and depth of the etching.

Francesco Prudenzano
Optical microresonators for biomedicine applications
D. Laneve, M.C. Falconi, G. Palma, A. Crudele, and F. Prudenzano
Department of Electrical and Information Engineering, Politecnico di Bari, Italy

The paper, after a brief review on optical microresonators for biomedicine, illustrates a set-up based on a praseodymium doped microdisk. It is more deeply described and a few design details are reported. This compact amplifier is based on chalcogenide Pr3+-doped microdisk coupled to two ridge waveguides. The gain close to G = 7.9 dB is simulated for an input signal power of -30 dBm at the wavelength of 4.7 μm and an input pump power of 50 mW at the wavelength of 1.55 μm. This kind of optical cavity could find application in biomedicine when active sensing is required.

Alexander Quandt
Solar cell device simulations
A. Quandt, R. Warmbier, I. Mokgosi, and T. Aslan
Materials for Energy Research Group and DST-NRF Centre of Excellence in Strong Materials, School of Physics, University of the Witwatersrand, Johannesburg, South Africa

Device simulations are a crucial part of the development of novel and more efficient types of solar cells. We give a brief introduction to the theoretical and numerical background of solar cell device simulations, and show that most of the key parameters may be taken from ab initio numerical data, rather than experimental data. We also discuss a simple strategy to implement up- and down-conversion layers into solar cell device simulations.

Giancarlo Righini
Light management in solar cells: Recent advances
G.C. Righini1,2, B. Boulard3, F. Coccetti1, F. Enrichi1,4, M. Ferrari1,5, A. Lukowiak6, S. Pelli1,2, L. Zur1,5, and A. Quandt1,7
1Historical Museum of Physics and Study & Research Centre "Enrico Fermi", Roma, Italy
2“Nello Carrara” Institute of Applied Physics, CNR-IFAC, Sesto Fiorentino, Italy
3IMMM - UMR CNRS 6283, Université du Maine, Le Mans, France
4Luleå University of Technology, Luleå, Sweden
5CNR-IFN, CSMFO Lab.& FBK Photonics, Povo-Trento, Italy
6Institute of Low Temperature and Structure Research, PAS, Wroclaw, Poland
7School of Physics and Materials for Energy Research Group, University of the Witwatersrand, Johannesburg, South Africa

Efficient light management is critical for the enhancement of the efficiency of solar cells.  The performance of a solar cell is determined by the efficiency of the absorption process of light via excitation of electron‐hole pairs and extraction of these generated charge carriers. The absorption, in turn, has a few limiting factors: one is related to the small size and acceptance angle of the active region, another to the reduced spectral sensitivity of the active material, which does not use a part of the solar radiation. Correspondingly, the energy harvesting may be improved in two ways: a) light trapping schemes may be adopted to make the cell “thicker” by exploiting scattering and/or reflection effects. Plasmonic structures, constituted by patterned metal films or nanoparticles, demonstrated to be very effective for directing and enhancing the incident light beam. b) up- and down-conversion processes may be exploited to convert the frequencies of the solar spectrum from near-mid-IR and from blue-UV regions, respectively, to the region of maximum absorption of the cell. Thin glassy or glass-ceramic films doped with rare earth ions proved to be very suitable for this purpose.  Here, an overview of recent results achieved in the use of plasmonic structures by different research groups will be reported, and different approaches will be compared.

Bouchta Sahraoui
Effect of UV irradiation on nonlinear optical response of azo-based iminopyridine rhenium complexes
K. Waszkowska1,3, B. Kulyk1, D. Guichaoua1, A.  Ayadi1,2,  A.  El-Ghayoury1, A. Zawadzka3, and B. Sahraoui1
1MOLTECH-Anjou Laboratory, UMR CNRS 6200, University of Angers, France
2 Laboratoire de Physico-Chimie de l’État Solide, Université de Sfax,  Sfax, Tunisia
3Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
The nonlinear optical properties of conjugated rhenium containing azo-based iminopyridine complexes were studied by means of Maker fringe technique using 30 ps laser pulses at 1064 nm. The influence of UV irradiation of guest-host films on nonlinear optical response was investigated. The values of second and third order susceptibility before and after UV irradiation were extracted and analyzed. The nonlinear optical response of the rhenium containing complex which contain lateral dimethylamino group and forms a D-A π-conjugated structure was found to be more sensitive to UV treatment.

Pablo Sanchis
Recent advances in strained silicon devices for enabling electro-optical functionalities
I. Olivares, T. Ivanova Angelova, A.M. Gutierrez, and P. Sanchis
Nanophotonics Technology Center, Universitat Politècnica de València, Spain

More than ten years ago it was demonstrated that the Pockels effect could be feasible by breaking the crystal symmetry of silicon. Since then, strained silicon devices have been developed by means of a highly stressing cladding layer (typically silicon nitride, SiN) deposited on top of the silicon waveguide. However, it has been recently shown that carrier effects could play a significant role and so the induced Pockels effect could have been overestimated. In this work, we will review the recent advances in the field and we will present our last results showing that there is also a strong influence of the interface traps on the electro-optical response.

Silvia Schintke
Printing and characterizing plasmonic nanoparticles
N. Fosso1, D.P. de Barros2, J. Krähenbühl1, and S. Schintke1
1Laboratory of Applied NanoSciences (COMATEC-LANS), University of Applied Sciences Western Switzerland (HES-SO), Yverdon-les-Bains, Switzerland
2Ecole de Physique Appliquée, INSA Toulouse, France

Printing plasmonic nanoparticles is of interest e.g. in the fields of large area printing for photovoltaic applications, biomedical and photonic sensor developments, as well as for digital printing of security tags for smart packaging and anti-counter fight applications. We have studied plasmonic gold nanoparticles embedded in printable PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), a transparent hole conducting organic semiconductor material).Aqueous dispersions of chemically stabilized gold nanoparticles (e.g. 40 nm in diameter) were used as plasmonic nanoparticle additives for the nanocomposite inks. Inkjet printing and coating has been performed on glass substrates. Inkjet printed nanocomposite microstructures and thin film coatings were investigated by true non-contact atomic force microscopy (AFM), optical microscopy and absorbance spectroscopy, as well as by electrical probing. The AFM topography and phase contrast data reveal individual nanoparticles and nanoparticle assemblies within the transparent conducting polymer coatings and printed structures. We compare and discuss the influence of different process and inkjet printing parameters used for the fabrication of printable plasmonic nanocomposite microstructures, as well as perspectives for device applications and manufacturing.

George Stanciu
Nanoscale imaging by using label free microscopy techniques
G.A. Stanciu,  D.E. Tranca, S.G. Stanciu, C. Stoichita, and R. Hristu
Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Romania

The objective of our work is connected with label free investigations at nanoscale by using a new multimodal microscopy system by using near field label free techniques. The system includes the techniques with hundred nanometers resolution and with few nanometers resolution, being able  to image simultaneously the same sample area giving complementary  information. Our system includes also an atomic force microscope. To image the human skin samples has been used two label free techniques working at nanoscale: scattering scanning near optical microscopy(s-SNOM) and second harmonic generation using an apertureless-scanning near optical microscope (SHG-SNOM).

Antonela Toma
Fractal analysis correlation of the images from scanning laser microscopy techniques and atomic force microscopy
A. Toma1, D.E. Tranca1, C.V. Sammut2, and G.A. Stanciu1
1Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Romania
2Department of Physics, Faculty of Science, University of Malta, Msida, Malta

The laser scanning laser microscopy (LSM) techniques and atomic force microscopy (AFM) give complementary information at micro and nano scales regarding the surface samples.  Lately we built a multimodal system based on far field and near field microscopy techniques upgraded with an atomic force microscope.  The system is able to acquire the optical images having hundred nanometers or nanometers resolutions.  Atomic force microscopy gives the information on topography at nanoscale.  Fractal analysis is a very useful tool for quantifying and simulating the complex patterns encountered in microscopic images.  The objective of this work is to perform a study of the complex optical and morphological features of certain biological tissues by using fractal geometry. It is shown a correlation between optical images and surface morphology regarding fractal geometry and that fractal dimension is a good candidate to quantify the different images.

Laurent Vivien
Subwavelength Si photonics for near- and mid-IR applications
C. Alonso-Ramos, D. Pérez-Galacho, D. Oser, X. Le Roux, D. Benedikovic, F. Mazeas, W. Zhang, S. Serna, V. Vakarin, E. Durán-Valdeiglesias, L. Labonte, S. Tanzilli, P. Cheben, E. Cassan, D. Marris-Morini, and L. Vivien
Institut d'Electronique Fondamentale, CNRS, Univ. Paris-Sud, Univ. Paris Saclay, Orsay, France

Periodically patterning Si with a pitch small enough to suppress diffraction, we synthesize an effective photonic medium with refractive index between those of Si and the cladding material. This technique releases new degrees of freedom in engineering of light-matter interaction, chromatic dispersion and light propagation in Si photonic waveguides. We report our advances in the development of subwavelength engineered structures for on-chip photonics circuits, including Si membrane waveguides for sensing applications in the near- and mid-infrared, and high pump-rejection filters for quantum photonics.

Anna Zawadzka
Physical vapor deposition technique and its application to thin organometallic films
A. Zawadzka1, P. Płóciennik1, K. Waszkowska1, Z. Masewicz1, A. Aamoum2, J. Strzelecki1, A. Korcala1, and B. Sahraoui3
1Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
2Laboratory of Condensed Matter Physics (LPMC), Faculty of Science, Chouaib Doukkal University, Eljadida, Morocco
3Institute of Sciences and Molecular Technologies of Angers MOLTECH Anjou - UMR CNRS 6200, France

This work contains description of the Physical Vapor Deposition technique and its application to selected organometallic thin films deposition process. We investigation results of the structural and optical properties of the thin films containing metal (M = Zn, Cu and Al) and bis- or tris(8-hydroxyquinoline). The films were successfully grown by physical vapor deposition (PVD) technique in high vacuum on transparent (quartz) and semiconductor (n-type silicon) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 24 hours at the temperature equal to 50°C, 100°C and 150°C. Spectral properties of these films were examined using classical and time-dependent photoluminescence investigations. Nonlinear optical effects were studied using Third Harmonic Generation and Z-Scan techniques. Structural properties were investigated by optical images and AFM measurements. The Mqn (n = 2 or 3) films exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. We find that the optical properties were strictly connected with the morphology and the temperature of annealing process can change the structural as well as optical properties of the films.

Yaping Zhang
FBG contact pressure sensitivity enhancement technology
Jichang Zhang1,2, S. Korposh1, R. Correia1, and Yaping Zhang2
1The University of Nottingham, UK
2University of Nottingham Ningbo China, China

This paper presents the simulation investigations on the enhancement technology on the contact pressure sensitivity of the Fibre Bragg Grating (FBG) sensor. The FBG was embedded in a patch made of polymer material in order to increase its pressure sensitivity. The polymer coating was able to convert the transverse pressure to longitudinal strain, which could further deform the FBG. The strain distribution was not uniform in the FBG patched layer and therefore the Bragg wavelength deviated from the theoretical result. The difference caused by the non-uniform strain distribution was investigated. The effect of temperature was eliminated by the use of a grating multiplexing technique. FBG was composed of multiple sub-gratings with different strain distributions. The transfer matrix of sub-gratings was calculated and integrated to obtain the final reflected spectrum of the FBG. With the patch layer coating, pressure sensitivity of a 1550 nm silica FBG was increased to 5 nm/MPa which was 1000 times higher than the original FBG without a patch. For the plastic FBG, the pressure sensitivity was increased to 0.169 µm/MPa.

WAOR invited presentations:

José Roberto Amazonas
Who shot optical packet switching?
J.R. de Almeida Amazonas1,2, G. Santos-Boada1, and J. Solé-Pareta1
1Department of Computer Architecture, Technical University of Catalonia, Barcelona, Spain
2Escola Politécnica of the University of São Paulo, Brazil

Looking at the volume of publications dealing with Optical Packet/Burst Switching (OPS/OBS) and those dealing with Elastic Optical Networking (EON) in the period from 2000 to 2016, one clearly can observe that between 2004 and 2009 there is a boom of the OPS/OBS publications and then they start to diminish. At the same time, EON publications start to take-off (around 2011) and is steadily growing. EON is an emerging technology that may be considered as a killer technology in the sense that its performance, flexibility, associated cost, ease of deployment and marketing seem to be displacing OPS/OBS from the optical networking arena. The purpose of this paper is discuss if, effectively, EON is the killer technology of OPS/OBS. So then, besides than review and compare the characteristics of each one of these technologies, the paper analyzes their similarities and dissimilarities as far as their actual deployment possibilities, as well as trying to identify if there is any condition  for the interest in OPS/OBS to regain momentum.

Andrea Bianco
On the importance of time-synchronized operations in software-defined electronic and optical networks
M. Garrich, A.S. Muqaddas, P. Giaccone, and A. Bianco
Dip. di Elettronica e Telecomunicazioni, Politecnico di Torino, Italy

The utilization of time-synchronized operations (TSO) is gaining interest in the research community on Software-Defined Networking (SDN). This paper discusses TSO applicability in electronic packet and optical networks. In electronic packet networks, the TSO approach has been shown to improve network performance, thanks to timed network updates. In optical networks, this approach enables novel security applications and permits to reduce lightpath disruption time. We finally discuss TSO further potentialities and requirements regarding clock availability in network elements.

Davide Careglio
Guaranteeing QoS requirements in long-haul RINA networks
S. Leon1, J. Perelló1, D. Careglio1, and M. Tarzan2
Universitat Politècnica de Catalunya (UPC)-BarcelonaTech, Barcelona, Spain
2Internet Architecture and Services, Fundacio i2CAT, Spain

In the last years, networking scenarios have been evolving, hand-in-hand with new and varied applications with heterogeneous Quality of Service (QoS) requirements. These requirements must be efficiently and effectively delivered.  Given its static layered structure and almost complete lack of built-in QoS support, the current TCP/IP-based Internet hinders such an evolution. In contrast, the clean-slate Recursive InterNetwork Architecture (RINA) proposes a new recursive and programmable networking model capable of evolving with the network requirements, solving in this way most, if not all, TCP/IP protocol stack limitations. Network providers can better deliver communication services across their networks by taking advantage of the RINA architecture and its support for QoS. This support allows providing complete information of the QoS needs of the supported traffic flows, and thus, fulfilment of these needs becomes possible. In this work, we focus on the importance of path selection to better ensure QoS guarantees in long-haul RINA networks. We propose and evaluate a programmable strategy for path selection based on flow QoS parameters, such as the maximum allowed latency and packet losses, comparing its performance against simple shortest-path, fastest-path and connection-oriented solutions.

Piero Castoldi
Segment routing in multi-layer networks
P. Castoldi1, A. Giorgetti1, A. Sgambelluri1, F. Paolucci1, and F. Cugini2
1Scuola Superiore Sant'Anna, Pisa, Italy
2CNIT, Pisa, Italy,

Segment Routing (SR) has been recently introduced to enable efficient traffic engineering while simplifying control plane operations. Thanks to the source routing paradigm, traffic flows can be dynamically routed along the network, effectively exploiting network resources. In this paper, dynamic SR operations for multi-layer networking are presented and experimentally demonstrated In particular, SR-based dynamic optical bypass and effective load balancing are validated in a multi-layer network testbed, showing enhanced capabilities to achieve effective resource utilization while guaranteeing lightweight control operations.

Jose Delgado Mendinueta
Ultra-high-capacity optical packet switching networks with coherent polarization division multiplexing modulation formats and related technologies
J.M. Delgado Mendinueta, S. Shinada, H. Furukawa, and N. Wada
Photonic Network System Laboratory, National Institute of Information and Communications Technology (NICT), Tokyo, Japan

Optical packet switching (OPS) technologies have a crucial function in current optical access networks and may be essential in future access and datacentre networks, where the requirements for higher data-rates, transparency, reduced end-to-end latency and optimized energy consumption may be enabled by increasing the network granularity and introducing flexibility on both the line-rate and the modulation format at the optical layer. This paper reviews recent research on two important subsystems of such new generation OPS networks: a digital coherent burst-mode receiver (DCBMRX) for PDM-QPSK and PDM-16QAM modulation formats and a line-rate flexible coherent burst-mode receiver. Finally, we discuss recent ultra-high capacity OPS experimental demonstrations, with top switching speeds of 12.8 Tb/s/port, that make use of the aforementioned DCBMRX and electro-optical switching matrices based on (Pb,La)(Zr,La)O3 (PLZT).The optical switching control plane is able to resolve packet contention by means of packet buffering and packet discarding.

Bing Han
Low phase noise optical burst transmitter for time and spectral optical aggregation solution
Bing Han, P. Gavignet, and E. Pincemin
Orange Labs Networks, Lannion, France

Sub-Lambda Photonically Switched Network (SLPSN) solutions are able to improve the use of capacity in data networks while limiting the growth of energy consumption. Recently, we have proposed the Time and Spectral optical Aggregation (TISA) solution in order to respond flexibly to customer’s requests while making better use of already deployed network resources. In TISA, each source sends data in the form of bursts that only occupies a spectral sub-band, thus offering purely optical aggregation and disaggregation in both time and spectral domains with the finest possible granularity. Wavelength-based routing is then performed passively in the network. A fast tunable laser with low phase noise is necessary to implement the TISA transmitter but, current existing commercial lasers can’t meet these two specifications. In this paper we present a transmitter solution fulfilling the switching time and low phase noise requirements. We give experimental results of a CO-MB-OFDM transmitter realized by combining optical gates and low phase noise lasers and report its performance in a back-to-back configuration.

Xavier Hesselbach
Optimal occupancy mapping of virtual networks over elastic optical infrastructures
P. Soto, J.F. Botero, and X. Hesselbach
Dept. Network Engineering, Universitat Politècnica de Catalunya (UPC), Barcelona, Spain

Network Virtualization acts as a key enabler of future networking paradigms. It allows multiple network architectures to coexist into the same shared physical topology. The main challenge in Network Virtualization deals with the efficient mapping of virtual resources onto physical resources. This is commonly referred by Virtual Optical Network Embedding (VONE) where the physical resources are optical. On the other hand, Elastic Optical Networks, are gaining more attention of researchers and industry due to their high spectrum efficiency, flexibility and adaptability allowing higher transmission rates able to cope with the tremendous IP traffic demand due to new application and services. In this paper, we propose a linear model to solve the offline version of VONE over EON-based physical networks including physical layer impairments, intrinsic to the operation of EONs, such as the transmission reach of robust modulation formats. Obtained results show that despite of the high complexity of the model, optimality can be reached to small and medium size instances of the problem.

David Larrabeiti
Design factors in multicast service delivery using the optical layer in core and metro networks
D. Larrabeiti1, G. Fernández-Del Carpio2, G. Otero1, and F.J. Ruiz-Piñar3
1Universidad Carlos III de Madrid, Spain
2Universidad Católica San Pablo Arequipa, Peru
3Universidad Politécnica de Madrid, Madrid, Spain

As optical switching and multiplexing architectures evolve, optical multicast keeps on being a capability advertised by a few core and transport optical equipment designers. However, up to the date, not much use of this service has been made by operators. This work addresses the reasons behind this fact, identifies the key technical design factors in a multicast-capable network and the challenges to face for an effective use of multicast at the optical layer.

Ariel Leiva López
A RMLSA algorithm with modulation format conversion at intermediate nodes
C. Garrido1, A. Leiva1, and A. Beghelli2
1Pontificia Universidad Católica de Valparaíso, Chile
2Universidad Adolfo Ibañez, Viña del Mar, Chile

In this paper a new RMLSA (Routing, Modulation Level, and Spectrum Assignment) algorithm is presented. The proposal leverages on the potential usage of intermediate modulation format conversion to increase the optical reach or being able to use route segments with lower available capacity.  To do so, the proposal first attempts to establish a full transparent connection on the shortest path. If this is not possible (due to optical reach limits or capacity availability), the algorithm resorts to modulation format conversion at an intermediate node. If modulation format conversion is not enough to establish the connection on the shortest path, up to two additional routes are explored.  By means of simulation, the performance of the algorithm was evaluated on a dynamic elastic optical network. Results show that, at low traffic loads (<0.4), resorting to modulation format conversion significantly decreases the rejection rate of connection requests compared to not applying such conversion.

Miklós Molnár
Non elementary routes for multicasting in transparent optical networks
M. Molnár, University Montpellier, LIRMM, France
Connection based networking is a basic technology for data transmission in Transparent Optical Networks (TON). In this kind of networks, important elements of the network design and management are related to the routing decisions in the optical level. To diminish the use of resources, multicasting is required for a lot of applications. Usually, multicast routes are light-trees in TONs. These trees should satisfy the known optical constraints. If it is not possible by a unique tree, "light-forests" are proposed. An alternative and more ergonomic solution called "light-hierarchy" was proposed to solve the multicast routing in constrained cases. We present this non-elementary structure and discuss the advantages and the difficulties of its computation. A related issue is the protection of multicast routes. Mainly segment-based and cycle-based protection schemes are proposed to protect routes against link and eventually node failures. The protection of branching nodes in multicast routes is more difficult. The route should re-established for all successors of the failed branching node and the optical constraints should be satisfied after the re-routing. To improve the protection, we also present non-elementary protection schemes for multicast routes. The aim of the propositions is to eliminate unnecessary constraints in route computations.

Ronald Romero Reyes
Analytical performance evaluation of connection setup latency in dynamic optical networks
R. Romero Reyes and T. Bauschert
Chair for Communication Networks, Technische Universität Chemnitz, Germany

With the emergence of flex-grid Wavelength Division Multiplexing (WDM) together with reconfigurable optical add/drop multiplexers and bandwidth-variable tunable transponders, a changeover from quasi-static to highly dynamic optical networks is expected. To perform resource allocation in such networks, signalling protocols that are able to rapidly set up optical connections are needed. In this paper, we present an analytical approach to evaluating the performance of an existing signalling protocol that provides fast connection setup in dynamic optical networks. The protocol is modelled as a task graph which represents the signalling latency during the connection establishment phase. By using reduction techniques, the graph is simplified so as to obtain a performance model that estimates the mean connection setup time. Simulations are used to validate the analytical performance model. The results show that the analytical model gives precise estimates of the mean connection setup time.

Gangxiang (Steven) Shen
Spectrum defragmentation and partial OTN switching in ultra-dense wavelength switched network (UD-WSN)
Ya Zhang1, Xu Zhou2, Yang Sheng1, Ning Deng2, and Gangxiang Shen1
1School of Electronic and Information Engineering, Soochow University, Suzhou, China
2Fixed Networks Research, Huawei Technologies Co., Ltd., Shenzhen, China

We have introduced a novel metro network architecture called Ultra-Dense Wavelength Switched Network (UD-WSN), which enables an even fine spectrum granularity so as to efficiently accommodate low-speed metro services (e.g., 1GE/10GE services). We evaluate the performance of this type of networks with spectrum defragmentation and partial optical transport network (OTN) switching. An efficient spectrum window plane (SWP)-based heuristic algorithm and a multi-layer traffic grooming algorithm based on an auxiliary graph (AG) for the OTN-based networks are developed for routing and spectrum resource allocation. Simulation results show that spectrum defragmentation based on a small granularity (e.g., 5 GHz) can achieve a bandwidth blocking probability (BBP) close to those of the pure OTN and the OTN over dense wavelength division multiplexing (DWDM) networks. A network with partial OTN switching capability can achieve a BBP close to the pure OTN and OTN over DWDM networks, while at a lower cost and power consumption.

Weiqiang Sun
Trading storage for bandwidth-A simulation study of optical circuit switching with massive storage at network edge
Fengqin Li, Weiqiang Sun, Shengnan Yue, and Weisheng Hu
State Key Laboratory of Advanced Optical Communications Systems and Networks, Shanghai Jiao Tong University, China

The network with massive storage at the switching nodes can store and forward bulk data from delay-insensitive applications. Increasing storage capacity can, under some circumstances, improve network throughput, like bandwidth does. In this paper, the effects of storage and bandwidth on OCS network performance and the principles of trading storage for bandwidth are discussed. Our research indicates that bandwidth is fair to flows with different sizes and is insensitive to different mean flow durations under the same load. On the contrary, the networks with massive storage are tend to discard larger flows and have favourable blocking rate to flows with smaller mean size. These results suggest that to achieve better performance in networks with mass storage, large flows should be split before transmitted to the network. Our research also suggests that the storage is particularly useful in handling bursty traffic.

Naoya Wada
Optical integrated network technologies for coping with traffic fluctuation and service diversification
N. Wada, H. Furukawa, J.M. Delgado Mendinueta, and S. Shinada
Photonic Network System Lab., National Institute of Information and Communications Technology (NICT), Tokyo, Japan

We develop an optical integrated network technology to cope with the rapid traffic fluctuation and the data service diversification. An optical packet and circuit integrated (OPCI) node can provide flexible optical paths for high quality of service, and dynamic optical packets for best-effort service on the same infrastructure. In this paper, we present a compatibility with various optical formats in an OPCI node consists of low polarization-dependent loss optical switches with nanosecond-order switching-speed and burst-mode amplifiers with low gain-fluctuation.

Last Updated on Tuesday, 20 June 2017 08:46