2019 Poster session 1

Evaluation of Stability of Silicon-Photonics-Based Optical Switch Network
Architectures against Parasitic Errors in Switch Elements

Banafsheh Abasahl , Wim Bogaerts
Ghent University – Imec, Technologiepark 126, 9052 Ghent, Belgium
Center of Nano-and Biophotonics, Ghent University, Ghent, Belgium e-mail: banafsheh.abasahl@imec.be

ABSTRACT
The performance of MEMS-based optical switch networks against losses and parasitic effects in tunable elements for different architectures are simulated. A comparison between those architectures is provided considering the fact that the parasitic effects of MEMS switches are highly depend on their status.
Keywords: optical switch networks, MEMS switches, Beneˇs, PILOSS, cross-bar, optical circuit simulation, stochastic analysis, errors.

Evaluation of Stability of Silicon-Photonics-Based Optical Switch Network Architectures against Parasitic Errors in Switch Elements


Large Q factor with small ring cavities
Nirmalendu Acharyya 1;2, Gregory Kozyreff 2
1Max-Born-Institut f¨ur Nichtlineare Optik und Kurzzeitspektroskopie,
D-12489 Berlin, Germany
2Optique Nonlin´eaire Th´eorique, Universit´e libre de Bruxelles (U.L.B.),
CP 231, Campus de la Plaine, 1050 Bruxelles, Belgium
e-mail: Nirmalendu.Acharyya@mbi-berlin.de, gkozyref@ulb.ac.be

ABSTRACT
Radiation losses are a critical problem of small-radius optical whispering gallery mode (WGM) resonators.
This phenomenon is a fundamental barrier that prevents one to reduce the size of the cavity and increase the local electric field. We propose a structure around the cavity that can be built with existing technologies and that can suppress the radiation. We demonstrate this fact by a nearly exact formula that gives the enhancement of the Q factor in 2D and confirm our results by a series of numerical simulations in 3D. By decreasing mode volume while preserving photon lifetime, the performance of WGM cavities can be boosted and new limits
can be reached in the many areas of research and applications where they are used, from cavity quantum electrodynamics to label-free biosensing.
Keywords: Whispering Gallery Modes, Bending losses, micro-ring resonators, small radius, Q factor.

Large Q factor with small ring cavities


Proposal of Integrated-Optical Circuit for Recognition of 8PSK-Coded label
for Photonic Label Router

Munkhbayar Adiya 1, Nyam-Erdene Odbayar 1, Hiroki Kishikawa 1, and Nobuo Goto 1
1Tokushima University, 2-1 Minamijosanjima-cho, Tokushima, 770-8506, Japan
Tel: +81-88-656-9418, e-mail: kishikawa.hiroki@tokushima-u.ac.jp

ABSTRACT
This paper discusses optical label recognition which is one of the key functions for photonic label routing. Previously, we have proposed a basic waveguide-type circuit for recognition of optical label encoded in quadrature-phase-shift-keying (QPSK) format. To increase the number of labels represented with the same
symbol number, we have studied 8-ary PSK (8PSK) recognition circuit based on the QPSK recognition circuit. The recognition of the proposed method is theoretically discussed and noise tolerance is also investigated.
Keywords: label recognition, optical 8PSK coded label, optical QPSK code, optical waveguide circuit, noise tolerance

Proposal of Integrated-Optical Circuit for Recognition of 8PSK-Coded label for Photonic Label Router


Monolithically Integrated Wavelength-Selective Switch on InP: a Circuit Simulation-Based Design Study
Alessandro Aimone1, Netsanet Tessema2, Kristif Prifti2, Rui Santos3, Nicola Calabretta2, André Richter1
1 VPIphotonics, Carnotstraße 6, 10587 Berlin, Germany
2 Eindhoven University of Technology, De Zaale, 5600 MB Eindhoven, Netherlands
3 SMART Photonics, High Tech Campus 29, 5656 AE, Eindhoven, Netherlands
e-mail: Alessandro.Aimone@vpiphotonics.com

ABSTRACT
Flexible optical networks have pushed the need for fast and compact switching elements. A wavelength selective switch consisting of passive arrayed waveguide gratings (AWG)-based multiplexers and demultiplexers and active semiconductor optical amplifier (SOA)-based optical switches is presented and analyzed in detail by means of hybrid time-and-frequency-domain simulations. The performance of the component is investigated and discussed.
Keywords: Wavelength Selective Switch, AWG, SOA, Elastic Networks, Simulations, Photonics.

Monolithically Integrated Wavelength-Selective Switch on InP: a Circuit Simulation-Based Design Study


Theoretical and Experimental Study of Distributed Bragg Reflector Lasers on SMART Photonics Platform (Student Paper)
Pengli An*, Andreas Hänsel, Martijn J. R. Heck
Aarhus University, Department of Engineering, Finlandsgade 22, 8200 Aarhus, Denmark
*e-mail: pengli_an@eng.au.dk

ABSTRACT
Photonic integrated circuits (PICs) provide the most promising way for tunable semiconductor lasers in reducing their size, weight, power consumption and cost. In this paper, theoretical and experimental research has dedicated on three-electrode Distributed Bragg reflector (DBR) lasers on indium phosphide (InP) PICs. Theory shows that the wavelength tuning could be realized by varying current injections to both DBR grating sections and SOA section. Experiment shows that DBR laser with 750-μm cavity length can be continuously tuned over 1.4 nm with side mode suppression ratio (SMSR) above 40 dB. Moreover, the linewidth of the laser is 4 MHz with 3 mW output power. Since these DBR lasers have been realized in a mature PIC platform following the design rules,
which means that they are now available as building blocks in larger-scale PICs.
Keywords: Distributed Bragg reflector lasers, tunable lasers, semiconductor laser, single-mode laser, photonic integrated circuits.

Theoretical and Experimental Study of Distributed Bragg Reflector Lasers on SMART Photonics Platform


Germanium Photodetector with Monolithically Integrated Narrowband Matching Network on a Silicon Photonics Platform
Laurens Bogaert1,2,*, Jochem Verbist1,2, Kasper Van Gasse1, Guy Torfs2, Johan Bauwelinck2, and Gunther Roelkens1
1 Photonics Research Group, Dept. INTEC, Ghent University–Imec, Technologiepark 126, 9052 Ghent, Belgium
2 IDLab, Dept. INTEC, Ghent University–Imec, Technologiepark 126, 9052 Ghent, Belgium
*e-mail: Laurens.Bogaert@ugent.be

ABSTRACT
High data rate transceivers typically consist of a system with hybrid integration of the electronics and photonics. Impedance levels provided by the opto-electronic device are often not the same as the levels desired by the electronic circuit. This mismatch introduces suboptimal operation and can even be detrimental for the overall system performance. Consequently, a matching circuit is often implemented on the electronic IC together with the main electronic functionality. Direct RF matching of the opto-electronic devices on the photonic IC has the potential to significantly reduce the overall system cost as the area cost of photonic chips is much lower. In this paper, narrowband LC-matching is shown for a germanium photodetector on the iSiPP50G silicon photonics platform to convert the output impedance to a more standard 50 Ω impedance level at 30 GHz. By tuning the photodetector reverse biasing voltage between 0 Volt and 3 Volt, a reflection coefficient lower than -20 dB is obtained over the frequency range between 24.3 and 30.4 GHz.
Keywords: Capacitors, Inductors, Narrowband matching, Photodetector, Radio-over-Fiber, Silicon photonics

Germanium Photodetector with Monolithically Integrated Narrowband Matching Network on a Silicon Photonics Platform


Flexible Integrated Silicon Photonic mm-Wave Frequency Upconversion Using GeSi EAMs
Laurens Breyne1, Jochem Verbist1,2, Jing Zhang1, Piet Demeester1, Gunther Roelkens1, Guy Torfs1
1Ghent University-imec, Technologiepark 126, 9052 Ghent – Belgium
2Now with BiFast, Belgium
e-mail: Laurens.Breyne@ugent.be

ABSTRACT
With Radio-Over-Fiber becoming an established technology for the next generation mobile communication networks, interest in integrated microwave photonic circuits is rapidly increasing. Especially photonic frequency converters receive quite some attention as they offer a very large bandwidth and high isolation. In this work, a flexible, integrated silicon photonic upconverter employing GeSi EAMs is demonstrated. The circuit performs frequency upconversion of IF as well as IQ baseband signals to an RF carrier. OSSB signals can be generated when IF upconversion is performed. We demonstrate IF upconversion from 3.5 GHz to 24-28 GHz of 87.5 Mbaud to 200 Mbaud 16QAM and 50 Mbaud 64QAM. EVMs are within the requirements of the 3GPP standard [1].
Keywords: Photonic Upconversion, Microwave Photonics, Radio-over-Fiber, Silicon Photonics

Flexible Integrated Silicon Photonic mm-Wave Frequency Upconversion Using GeSi EAMs


On the characterization of integrated power splitters and waveguide losses using optical frequency domain interferometry (Student paper)
Luis A. Bru,1 Daniel Pastor,1 and Pascual Mu˜noz1; 2
1Universitat Politecnica de Valencia, c/ Camino de Vera s/n – 46021 Valencia – Spain
email: dpastor@dcom.upv.es
2VLC Photonics S.L., c/ Camino de Vera s/n – 46021 Valencia – Spain

ABSTRACT
In this paper, we propose a technique to characterize integrated power splitters and waveguide losses. Taking advantage of the time domain resolution of an optical frequency domain interferometry measurement, we present two versions of a test device comprising interferometers and the power splitters under test providing a mean to characterize the splitting power ratio of them and the losses of the employed integrated waveguides, in a single (or double) measurement wavelength-resolved scheme. We provide details on the model and examples of the numerical work supporting its validity. To conclude, we provide some discussion of the techinque, including the possible implementations for future experimental validation.
Keywords: optical frequency domain reflectometry, power splitter, multimode interferometer, integrated test structure, integrated waveguide losses.

On the characterization of integrated power splitters and waveguide losses using optical frequency domain interferometry


Compact Cavity Enhanced Si MSM Photodetector in SiN-on-SOI (Student paper)
Avijit Chatterjee1, Shankar Kumar Selvaraja1
1 Center for Nano Science and Engineering, Indian Institute of Science, Bangalore
e-mail: avijit@iisc.ac.in

ABSTRACT
We present compact Si metal semiconductor metal (MSM) photodetector integrated SiN ring resonator in SiN-on-SOI platform. We achieved a 10X enhancement in photocurrent with SiN resonator integrated photodetector compared to integrated waveguide configuration. A maximum responsivity of 0.08 A/W is achieved with a photodetector of just 6 μm long operated at a bias of 5 V in the 850 nm wavelength band. We present the design, fabrication and characterisation of integrated resonance photodetector. On-chip wavelength selective photodetector in 850 nm wavelength band enables next-generation scalable short-reach interconnect technology and also an opportunity for on-chip bio-sensors operating in the visible wavelength range.
Keywords: SiN-SOI, MSM photodetector, Ring resonator

Compact Cavity Enhanced Si MSM Photodetector in SiN-on-SOI


Investigation of the Background Signal from 532 nm Excitation for Waveguide-based Raman Spectroscopy and Microscopy (Student paper)
David A. Coucheron1, Dushan N. Wadduwage2,3,4, Ganapathy S. Murugan5, Peter T. C. So2,3, Balpreet S. Ahluwahlia1
1 Department of Physics and Technology, UiT – The Arctic University of Norway, Norway
2 Laser Biomedical Research Center, Massachusetts Institute of Technology, Massachusetts 02139, USA
3 Department of Biological Engineering, Massachusetts Institute of Technology, Massachusetts 02139, USA
4 Center for Advanced Imaging, Harvard University, Cambridge MA, 02138, USA
5 Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, United Kingdom
e-mail: balpreet.singh.ahluwalia@uit.no

ABSTRACT
The simple integrated waveguide has found many new applications recently, including waveguide enhanced Raman spectroscopy and chip based super-resolution microscopy. Chip based microscopy relies exclusively on visible light excitation, whereas Raman spectroscopy is done at a range of wavelengths. Here, we investigate two popular waveguide platform, Si3N4 and Ta2O5, for use at 532 nm excitation. We also present spontaneous Raman spectroscopy of methanol and iso-propanol using Ta2O5 strip waveguides and 532 nm excitation light.
Keywords: Waveguide, Raman spectroscopy, super-resolution imaging

Investigation of the Background Signal from 532 nm Excitation for Waveguide-based Raman Spectroscopy and Microscopy


Slepian-States-based DV- and CV-QKD Schemes Suitable for Implementation in Integrated Optics
Ivan B Djordjevic
University of Arizona, ECE Dept., 1230 E Speedway Blvd, Tucson, AZ 85721 – USA
e-mail: ivan@email.arizona.edu

ABSTRACT
To solve for low secret-key-rate (SKR) and short-distance problems of QKD in a simultaneous manner, we propose to encode information in orthogonal Slepian sequences’ bases. Employment of multidimensional encoding-space enables high-spectral-efficiency-QKD so that SKR can be significantly improved. Generation, processing, and detection of Slepian-states for proposed QKD-protocols can be reliably implemented in an integrated optics platform, based on waveguide Bragg gratings.
Keywords: Quantum key distribution (QKD), Slepian-states, integrated optics, waveguide Bragg gratings. 1.

Slepian-States-based DV- and CV-QKD Schemes Suitable for Implementation in Integrated Optics


Shaping the optical properties of carbon nanotubes via chirality-selective resonant enhancement in silicon micro-ring resonators
Elena Durán-Valdeiglesias1,*, Weiwei Zhang1,†, Carlos Alonso-Ramos1, Samuel Serna1, Xavier Le Roux1, Delphine Marris-Morini1, Marta Reig2, Niccolò Casselli3, Francesco Biccari3, Massimo Gurioli3, Arianna Filoramo2, Eric Cassan1, and Laurent Vivien1
1 Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, C2N, Orsay 91405, France
2 CEA Saclay, IRAMIS, NIMBE (UMR 3685), LICSEN, Bât. 125, F-91191 Gif-sur-Yvette, France
3 Department of Physics, University of Florence. European Laboratory for Non-linear Spectroscopy, 50019 Sesto Fiorentino (FI), Italy
e-mail: Elena.Duran@u-psud.fr
† Current address: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK

ABSTRACT
Semiconducting single walled carbon nanotubes (s-SWNT) have an immense potential for the development of light sources in the silicon photonics platform. However, two major challenges still need to be addressed: the limited interaction between s-SWNTs and Si waveguides and the single-chirality selection. Silicon micro-ring resonators may overcome the first limitation by exploiting resonant light recirculation. Here, we demonstrate that Si ring resonators can also provide SWNT chirality-selective photoluminescence resonance enhancement, releasing a new degree of freedom to shape the optical properties of s-SWNT. Specifically, we experimentally show selective emission enhancement of either (8,6) or (8,7) SWNT chiralities present in a high-purity polymer-sorted s-SWNT solution by judicious micro-ring geometry design. In addition, we harness the large index contrast of the Si platform to experimentally demonstrate that, opposite to the common knowledge, transverse-magnetic (TM) optical modes can efficiently interact with drop-casted s-SWNTs arranged along the chip surface.
Keywords: carbon nanotubes, hybrid silicon photonics, photoluminescence.

Shaping the optical properties of carbon nanotubes via chirality-selective resonant enhancement in silicon micro-ring resonators


Design and analysis of an integrated widely tunable laser
Andreas Hänsel, Martijn J.R. Heck
Aarhus University – Department of Engineering, Finlandsgade 22, 8200 Aarhus, Denmark
e-mail: A.Hansel@eng.au.dk

ABSTRACT
We report our work on a widely tunable laser to be used for gas sensor applications. The laser design is inspired by earlier work using an intra-cavity filter combining three asymmetric Mach-Zehnder interferometers. In our reworked design, intra-cavity losses and footprint are drastically reduced. We compare calculated outputs with data obtained from our measurements. We achieved a tuning range of more than 10 nm with output powers in the mW range.
Keywords: indium phosphide, gas spectroscopy, photonic integrated circuits, tunable laser

Design and analysis of an integrated widely tunable laser


Heavily doped Er3+/Yb3+planar waveguides on silica for high gain per unit
length amplification in the C-band
(Student Paper)
Eduardo Henriques Dos Santos 1, Billy Richards 1, Eric Kumi Barimah 1, Paul Farrugia 2, Gin Jose 1
1 School of Chemical and Process Engineering, University of Leeds, Clarendon Road, Leeds, United Kingdom
2 XTERA, Bates House, Church Road, Harold Wood, Essex, United Kingdom
e-mail: pm14ehds@leeds.ac.uk

ABSTRACT
This paper explores potential design and the likely characteristics of an Er3+/Yb3+co-doped waveguide amplifier based on a planar waveguide fabricated using the ultrafast laser plasma implantation method. Using this technique a layer of silica glass is modified by the implantation of tellurite glass particles in a silica glass substrate, resulting in a rare earth rich region with demonstrated concentrations of up to 1.63x1027atoms/m3. Experimental measurements of a planar waveguide’s properties are shown and the theoretical gain achievable
is calculated using numerical simulations, resulting in a value of 9.5 dB/cm and a theoretical maximum of 27 dB/cm.
Keywords: Waveguide amplifiers, Erbium/Ytterbium co-doped, modelling, spectroscopy, optical communications

Heavily doped Er3+/Yb3+planar waveguides on silica for high gain per unit
length amplification in the C-band


Novel Concept for Polarization Splitting in InP Platforms
Shahram Keyvaninia, Patrick Runge, Frederik Schröder and Martin Schell
Fraunhofer Heinrich-Hertz-Institute, Einsteinufer 37, 10587 Berlin, Germany
e-mail: shahram.keyvaninia@hhi.fraunhofer.de

ABSTRACT
A novel concept for the monolithic integration of a polarization beam splitter (PBS) on InP platforms is presented. The device is utilizing a waveguide integrated 1×2 power splitter, a variable optical attenuator (VOA) and a semiconductor optical amplifier (SOA) both based on multiple-quantum wells (MQWs). The separation of TE- and TM- polarized light is resulting from the power splitter and the different absorption and amplification coefficients in MQW-VOA and MQW-SOA. By engineering the power-splitting ratio and the MQW structure a high polarization extension ratio (PER) of above 20 dB for both polarizations over more than 40 nm optical bandwidth can be achieved.
Keywords: PBS, InP integration, VOA, SOA, polarization multiplexing, polarization diversity, photodetector

Novel Concept for Polarization Splitting in InP Platforms


Extracting Coupling Coefficients of Directional Couplers.
Umar Khan 1;2, Yufei Xing 1;2, Antonio Ribeiro 1;2, Wim Bogaerts 1;2
1Ghent University – imec, Technologiepark 126, 9052 Ghent, Belgium
2Center for Nano- and Biophotonics, Ghent University, Belgium
e-mail: Umar.Khan@ugent.be

ABSTRACT
We experimentally demonstrate the extraction of dispersive directional coupler parameters (coupling coefficients) using optical transmission measurements. The coupling coefficients are extracted using both direct transmission of directional couplers and through more complex Mach-Zehnder interferometers (MZI) and we conclude that coefficients using the MZI circuits give better accuracy.
Keywords: silicon photonics, directional couplers, parameter extraction, coupling coefficients, behavioral model, spectrum fitting.

Extracting Coupling Coefficients of Directional Couplers


Distributed Phase Shift and Lasing Wavelength in Distributed-Feedback Resonators
Cristine C. Kores1, Nur Ismail2, Edward H. Bernhardi3, Fredrik Laurell1, Markus Pollnau2,4
1 Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
2 Department of Materials and Nano Physics, Royal Institute of Technology, Kista, Sweden
3 Visiting Scientist, Department of Materials and Nano Physics, Royal Institute of Technology, Kista, Sweden
4 Advanced Technology Institute, University of Surrey, Guildford, United Kingdom
e-mail: m.pollnau@surrey.ac.uk

ABSTRACT
Distributed-feedback waveguide lasers based on Bragg-grating resonators generate ultranarrow-linewidth emission. The required /2 phase shift is often introduced by a distributed change in effective refractive index, e.g. by adiabatically widening the waveguide. Despite careful design and fabrication, the experimentally observed resonance wavelength deviates, thereby placing the resonance and laser emission at a position with lower reflectivity inside the reflection band. This effect is often incorrectly attributed to fabrication errors. Here we show theoretically and experimentally that the decay of light intensity during propagation from the phase-shift center into both sides of the Bragg grating due to (i) reflection by the periodic grating and (ii) the adiabatic refractiveindex change causes an incomplete accumulation of designed phase shift, thereby systematically shifting the resonance to a shorter wavelength. Calculations based on the characteristic-matrix approach and experimental
studies in a distributed-feedback channel-waveguide resonator in amorphous Al2O3 on silicon with a distributed phase shift introduced by adiabatic widening of the waveguide according to a sin2 function show good agreement.
Keywords: Integrated Lasers, Distributed-feedback lasers, Optical resonators, Laser resonators, Bragg reflectors.

Distributed Phase Shift and Lasing Wavelength in Distributed-Feedback Resonators


Multi-Band Gap Electro-Absorption Modulator Array in a Generic Integration Platform using Selective Area Growth (Student paper)
Florian Lemaitre1, Marija Trajkovic1, Jean Decobert2, Huub Ambrosius1, Kevin Williams1
1Institute for Photonic Integration, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
2III–V Lab, Campus de Polytechnique, 1 avenue Augustin Fresnel, F-91767 Palaiseau Cedex, France
e-mail: f.lemaitre@tue.nl

ABSTRACT
We demonstrate the integration of 4 electro-absorption modulators (EAM) with shifted band gaps by combining selective area growth (SAG) with a generic photonic integration platform. The designed, fabricated and characterized EAMs operate in the wavelength range 1490–1550 nm, and the process allows mask layer specification of four band-gaps with 20 nm spacing. Static extinction ratio over a 2V peak-to-peak voltage swing is beyond 10 dB for all EAMs with a variation of only 1.7 dB from device to device over the 60 nm wavelength range.
Keywords: Selective Area Growth, Generic photonic integration platform, Electro-Absorption Modulator

Multi-Band Gap Electro-Absorption Modulator Array in a Generic Integration Platform using Selective Area Growth


Intrinsic Limit of Detection for Coherent Biosensing Systems Student Paper
Jonas Leuermann1;2, ´I ˜nigo Molina-Fern´andez1;2, Alejandro Ortega-Mo˜nux1;2,
J. Gonzalo Wang¨uemert-P´erez1;2, Robert Halir1;2
1 Bionand Center for Nanomedicine and Biotechnology,
Parque Tecnol´ogico de Andaluc´ıa, 29590 M´alaga, Spain
2 Universidad de M´alaga, Dept. de Ingenier´ıa de Comunicaciones, ETSI Telecomunicaci´on,
Campus de Teatinos s/n, 29071 M´alaga, Spain
 Corresponding author: jleuermann@bionand.es

ABSTRACT
Optical biosensors have drawn great interest in the last years as they are able to detect trace amounts of biochemical substances without prior labeling. Interferometric structures with coherent phase read-out have recently shown to exhibit state-of-the-art limits of detections. Their fixed wavelength read-out system makes them a promising candidate for point-of-care devices for which cost is a critical factor. Over the last years the sensing community has mainly focused on the design of highly sensitive structures while little attention has
been paid to the fundamental noise sources of the complete system and their influence on the optimization on the limit of detection. In this work, we analyze these noise and provide a series of guidelines to reach the fundamental limit of detection of coherent interferometric biosensors.
Keywords: photonic biosensor, Mach-Zehnder interferometer, coherent detection, fundamental limit of detection,
evanescent field sensing

Intrinsic Limit of Detection for Coherent Biosensing Systems


Design of slot waveguide for ultra-violet light based on atomic layer deposition
Chupao Lin1,2, Roel Baets1,2, Gunther Roelkens1,2 and Nicolas Le Thomas1,2
1Photonics Research Group, INTEC Department, Ghent University-imec, Technologiepark-Zwijnaarde, 9052 Ghent, Belgium
2Center for Nano- and Biophotonics, Ghent University, Belgium
e-mail: Nicolas.LeThomas@ugent.be

Abstract
We unveil parameter sets to achieve a low loss single mode waveguide operating at UV wavelengths. The proposed design that is compatible with atomic layer deposition technology is expected to have potential applications in integrated-photonics based UV sensing.
Keywords: Ultraviolet; Photonic integrated circuits; Guided waves

Design of slot waveguide for ultra-violet light based on atomic layer deposition


On-chip integrated resonators for long-wave infrared photonics (Student Paper)
Qiankun Liu1,*, Joan Manel Ramirez1,3, Vladyslav Vakarin1, Xavier Le Roux1, Jacopo Frigerio2, Andrea Ballabio2, Miguel Montesinos1, Carlos Alonso-Ramos1, Enrico Talamas Simola2, Laurent Vivien1, Giovanni Isella1, and Delphine Marris-Morini1
1 Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris Sud, CNRS, Université Paris Saclay, 91120 Palaiseau, France
2 L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, 22100 Como, Italy
3 Now at III-V lab, a joint lab from Nokia Bell Labs, Thales and CEA, 1 avenue Augustin Fresnel, 91767 Palaiseau Cedex
e-mail: qiankun.liu@u-psud.fr

ABSTRACT
On-chip optical resonators are extensively applied to many fields such as light sources through lasing or enhancement of material nonlinear effects, chemical and biological sensing, and optical network monitoring. Silicon-based on-chip resonators have been reported previously in near infrared (NIR) and short-wave infrared (SWIR), however integrated resonant structures remain still challenging for long-wave infrared (LWIR). In this work, we experimentally demonstrate the first on-chip integrated resonators in LWIR up to 8.4 μm. Two types of resonators, Fabry-Perot cavities and racetrack ring resonators have been both investigated. Loaded quality factors Q = 2200 and Q = 3200 have been respectively observed for Fabry-Perot cavity and racetrack ring resonator at a wavelength around 8 μm.
Keywords: Integrated optics devices, Mid-infrared, Fabry-Perot cavities, Racetrack ring resonators.

On-chip integrated resonators for long-wave infrared photonics


On the Performance of Tantalum Pentoxide and Silicon Nitride Slot Waveguides for On-Chip Raman Spectroscopy (Student paper)
Zuyang Liu 1;2, Haolan Zhao 1;2, Ali Raza 1;2, Nicolas Le Thomas 1;2, and Roel Baets 1;2
1Photonics Research Group, INTEC Department, Ghent University-imec, 9052 Ghent, Belgium
2Center for Nano- and Biophotonics, Ghent University, 9052 Ghent, Belgium
e-mail: Zuyang.Liu@ugent.be

ABSTRACT
Waveguide-enhanced Raman spectroscopy is a promising technique for high-sensitivity molecular identification and quantification. Efficient on-chip Raman spectroscopy demands high-index-contrast waveguide platforms and a reduced photonic Raman background of the waveguide core material. Tantalum pentoxide
is recently emerging as a novel CMOS compatible integrated platform. It has a moderately high refractive index of 2.11, along with a low Raman background. In this article, we investigate and identify the optimal waveguide geometry of tantalum pentoxide slot waveguides to reach the highest overall Raman collection efficiency and lowest waveguide background. Compared to the widely used silicon nitride waveguide platform, tantalum pentoxide waveguides delivers 4 times better performance concerning signal-to-noise ratio (SNR), assuming similar waveguide loss values.
Keywords: On-chip Raman spectroscopy, waveguide sensor, high-index-contrast platforms

On the Performance of Tantalum Pentoxide and Silicon Nitride Slot Waveguides for On-Chip Raman Spectroscopy


High accuracy transfer printing of III-V/SOI micro-disk resonators for non-linear applications
John McPhillimy1, Charalambos Klitis2, Stuart May2, Benoit Guilhabert1, Martin D. Dawson1, Marc Sorel2, and Michael J. Strain1
1 Institute of Photonics, Dept. of Physics, University of Strathclyde, Glasgow G1 1RD, UK
2 School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
e-mail: john.mcphillimy@strath.ac.uk

ABSTRACT
In this paper, we report on the heterogeneous integration of III-V-on-silicon micro-disk resonators using our high alignment accuracy transfer printing method, exhibiting loaded quality factors of ≈2.5×104. High absolute positional printing accuracy allows control over the devices lateral coupling gap to the silicon bus waveguide, enabling selective resonant mode excitation within the multimode micro-disk. We further report efficient non-linear conversion by four-wave mixing. A conversion efficiency of -25dB is obtained at an on-chip optical power of 2.5mW.
Keywords: Photonic Integrated Circuits, Hybrid integration, Transfer Printing, Silicon photonics, III-V semiconductors, Nonlinear optics

High accuracy transfer printing of III-V/SOI micro-disk resonators for non-linear applications


Silicon Slot Waveguide based Bulk Refractive Index Sensing of Electrolyte and Carbohydrate (Student Paper)
Viphretuo Mere,1, Hemalatha Muthuganesan1, Pallavi Dasgupta1, Navakanta Bhat1 and Shankar Kumar Selvaraja1
1Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, India.
e-mail: shankarks@iisc.ac.in

ABSTRACT
In this paper, we present a slot waveguide-based on-chip bulk refractive index sensing of liquids. We experimentally demonstrate a slot-based ring resonator with a spectral sensitivity of 363 nm/RIU. We experimentally show sensing of refractive index potassium chloride various concentration and verified with Abbe refractometer. Finally, we experimentally investigated simultaneous absorption and refractive index sensing of glucose.
Keywords: slot waveguide, ring resonator, absorption sensing, photonic integrated circuit, silicon photonics.

Silicon Slot Waveguide based Bulk Refractive Index Sensing of Electrolyte and Carbohydrate


Automatic look up table generation technique for photonic integrated circuits (Student Paper)
Maziyar Milanizadeh, Douglas Aguiar, Francesco Morichetti and Andrea Melloni
Dipartimento di Elettronica, Informazione e Bioingegneria – Politecnico di Milano,
Milano, 20133 Italy
e-mail: maziyar.milanizadeh@polimi.it

ABSTRACT
In this work we presented a technique which can be adopted to create automatically and efficiently lookup tables for arbitrary photonic integrated circuits compensating for external perturbations like thermal crosstalk. Its
performance is experimentally examined in coupled microring resonators implemented in silicon photonics. These lookup tables can dynamically update themselves to new conditions of the chip upon the need.
Keywords: Automatic tuning algorithm, lookup table, thermal crosstalk

Automatic look up table generation technique for photonic integrated circuits


Chip-based compact squeezing experiment at a telecom wavelength
François Mondain1, Tommaso Lunghi1, Alessandro Zavatta2,3, Élie Gouzien1, Florent Doutre1, Marc de Micheli1, Sébastien Tanzilli1, and Virginia D’Auria1
1 Université Côte d’Azur, Institut de Physique de Nice (INPHYNI), CNRS UMR 7010, Nice- France
2 Istituto Nazionale di Ottica (INO-CNR) Largo Enrico Fermi 6, 50125 Firenze, Italy;
3LENS and Department of Physics, Universitá di Firenze, 50019 Sesto Fiorentino, Firenze, Italy.
e-mail: virginia.dauria@univ-cotedazur.fr

ABSTRACT
We present a compact and easy-to-use set-up exploiting the association of commercial plug-and-play fibre components and integrated optics on lithium niobate for the generation and detection of squeezed light at a telecom wavelength. Light exhibits a reduced quantum noise of -2.00±0.05 dB below the shot-noise level in a single-pass configuration.
Keywords: Quantum communication; integrated optics; Squeezed states; Lithium Niobate; Homodyning.

Chip-based compact squeezing experiment at a telecom wavelength


Photonic Crystal/Photonic Wire Multiple-micro-cavity Structure
Mohd Nuriman Nawi1, Dilla Duryha Berhanuddin1, Ahmad Rifqi Md Zain1,2, Richard M. De La Rue3
1 Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43600, Bangi, Selangor, Malaysia
2 John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, 02138, United States
3 Optoelectronics Research Group, School of Engineering, Rankine Building, Oakfield Avenue, University of Glasgow, Glasgow G12 8LT, UK
e-mail: rifqi@ukm.edu.my

ABSTRACT
We present a study of triple-cavity 1-dimensional (1D) photonic crystal structures embedded in silicon photonic wire (PhC/PhW). Three cavity resonance wavelengths were observed. Structures with a greater number of resonance wavelengths would result from increasing the number of coupled cavities. The structure was designed to operate at fibre telecommunication wavelengths where all the resonance wavelengths fall in the C and L band regions. Factors that define the performance of the device – such as wavelength selectivity, resonance quality factor and transmission magnitude can be controlled by precise definition and simulation of the photonic crystal micro-cavity. The accuracy of the prediction of the resonance wavelengths was evaluated in both simulation and experiment, with good agreement between them. This approach is promising for exploitation in photonic integrated circuits (PICs) for wavelength division multiplexing (WDM) applications, providing a possible solution for smaller footprint devices.
Keywords: multiple-resonance, multiple-cavity, micro-cavity, 1D photonic crystal, wavelength division multiplexing, photonic integrated circuit.

Photonic Crystal/Photonic Wire Multiple-micro-cavity Structure


Integrated pump rejection filter for high-quality photonic quantum
communication

Dorian Oser 1, Florent Mazeas 2, Carlos Alonso Ramos 1, Xavier Le Roux 1,
Laurent Vivien 1, S´ebastien Tanzilli 2, ´ Eric Cassan 1, Laurent Labont´e 2
1Centre de Nanosciences et de Nanotechnologies, CNRS, Universi´e Paris-Sud, Universit´e Paris-Saclay,
C2N, Palaiseau, France
2Universit´e Cˆote d’Azur, CNRS, Institut de physique de Nice, France
e-mail: dorian.oser@c2n.upsaclay.fr

ABSTRACT
Combining quantum and integrated photonics gives the ability of generating, manipulating, and detecting individual quantum states on single chips. Nonlinear four-wave mixing in silicon micro-ring resonators has shown an immense potential for on-chip bright photon-pair generation. However, one of the major challenges of this approach is the on-chip rejection of the pump, which severely distorts the quantum signals generated by the nonlinear process. Here, we report the integration on a single substrate of a photon-pair generator and a pump-rejection filter showing photon pair generation with a rate of 480 pairs per second for two signal/idler pairs simultaneously, with a brightness of 390 pairs/s/MHz, and a remarkably high raw visibility exceeding 95 %. All wavelengths fall within the ITU channels thus rendering this photon-pair source compatible with off-the-shelf telecom components.
Keywords: ring resonator, photonics, SFWM, multimode, Bragg filters.

Integrated pump rejection filter for high-quality photonic quantum
communication


Non-Volatile and Ultra-Compact Photonic Memory (Student paper)
Jorge Parra1,*, Irene Olivares1, Antoine Brimont1, Juan Luis Frieiro2, Oriol Blázquez2, Sergi Hernández2, Blas Garrido2 and Pablo Sanchis1,+
1 Nanophotonics Technology Center, Universitat Politècnica de València,
Camino de Vera s/n, 46022 Valencia, Spain
2 MIND, Department of Electronics and Biomedical Engineering, Universitat de Barcelona,
Martí i Franquès 1, E-08028 Barcelona, Spain
e-mail: *jorpargo@ntc.upv.es, +pabsanki@ntc.upv.es

ABSTRACT
In this work, we propose a non-volatile and ultra-compact photonic flash memory by utilizing a transparent conducting oxide (TCO) as a floating gate. The memory acts as a non-volatile electro-absorption switch and exploits the epsilon-near-zero regime (ENZ) of the TCO floating gate for enabling the switching between two states with low and high optical losses. Our simulation shows that, by means of applying +11 V and –11 V voltage pulses, the memory is programmed or erased, respectively. Additionally, for a 5-μm-long device, the memory features negligible insertion losses and an optical extinction ratio of 35 dB with an inherent broadband wavelength operation due to its non-resonant response. This device could pave the way for developing high-density photonic memory banks on the silicon photonics platform.
Keywords: optical memory, non-volatile, epsilon-near-zero, transparent conducting oxides, silicon photonics.

Non-Volatile and Ultra-Compact Photonic Memory


Investigation of the Dynamical Behaviour of Mutually Coupled Lasers on a
Photonic Integrated Circuit
(Student Paper)
Alison H. Perrott 1;2, Mohamad Dernaika 1;2, Ludovic Caro 1;2, Frank H. Peters 1;2
1University College Cork, Cork, Ireland
2Tyndall National Institute, Cork, Ireland
e-mail: alison.perrott@tyndall.ie

ABSTRACT
In this paper, we investigate the mutual injection locking properties of a photonic integrated circuit consisting of two slotted Fabry-P´erot lasers coupled together through a 1.1 mm variable optical attenuator/amplifier. The output of the lasers was observed on an electrical spectrum analyser, optical spectrum analyser and a high speed oscilloscope. Various types of dynamical behaviour were identified as a function of the coupling and the detuning between the lasers.
Keywords: Mutual injection locking, coupled lasers, photonic integration, laser dynamics.

Investigation of the Dynamical Behaviour of Mutually Coupled Lasers on a
Photonic Integrated Circuit


InP-on-Si DFB Laser Diode with Distributed Reflector for Improved Power Efficiency (Student paper)
Mahmoud Shahin1,2, Joris Van Kerrebrouck3, Gunther Roelkens1,2, Geert Morthier1,2
1 Ghent University-imec, Technologiepark 15, Ghent, Belgium
2 Center for Nano- and Biophotonics, Ghent University, Ghent, Belgium
3 IDLab, Ghent University – imec, Ghent, Belgium
E-mail: Mahmoud.Shahin@ugent.be

ABSTRACT
A heterogeneously integrated InP-on-Si DFB laser diode with an active distributed reflector is demonstrated. The goal is to improve the power efficiency of the laser, by reducing the threshold current, and obtaining similar 3-dB modulation bandwidth with similar optical output power levels to previously demonstrated lasers, at lower injected current values. The device was first fabricated as a standard single-section DFB laser, then electrically isolated in two sections with unequal lengths. The shorter section is pumped and acts as an active laser section, while the other section is not pumped and acts as an absorbing distributed reflector. The threshold current was reduced from 17 mA to 9 mA, and the bias current required to achieve similar 3-dB modulation bandwidth to previously demonstrated lasers was reduced from 100 mA to 45 mA. Transmission of a 28 Gbps NRZ-OOK signal for both a back-to-back configuration and over 2 km of NZ-DS fiber is demonstrated, with bit-error-rate below the hard-decision forward-error-correction threshold.
Keywords: InP-on-Si, distributed feedback lasers, silicon photonics.

InP-on-Si DFB Laser Diode with Distributed Reflector for Improved Power Efficiency


Novel adiabatic tapered coupler for small III-V lasers grown on SOI wafer
Yuting Shi 1, Bernardette Kunert 2,Marianna, Pantouvaki 2, Joris Van Campenhout 2,Dries Van Thourhout 1;2
1INTEC Department, Ghent University, Technologiepark-Zwijnaarde 126, 9052 Ghent, Belgium
2IMEC, Kapeldreef 75, 3001 Heverlee, Belgium
e-mail: Yuting.Shi@ugent.be

ABSTRACT
While III-V lasers epitaxially grown on silicon have been demonstrated, an efficient approach for coupling them with a Silicon Photonics platform is still missing. In this paper, we present a novel design for an adiabatic coupler for interfacing nanometer scale III-V lasers grown on SOI with other silicon photonics components. The starting point is a directional coupler, which achieves 100% coupling efficiency from the III-V lasing mode to the Si waveguide TE-like ground mode. To improve the robustness and manufacturability of the coupler, a more advance tapered coupler is designed, which is less sensitive to variations in III-V waveguide dimensions and temperature variations, and still reaches a coupling efficiency close to 100%. The proposed couplers are designed for the particular case of aspect-ratio-trapping (ART) based III-V epitaxy, but it is believed that it
should also be compatible with other epitaxial III-V/Si integration platforms. The presented coupler is expected to pave the way to integrating III-V lasers epitaxially grown on SOI wafers with other photonics components, one step closer towards a fully functional Silicon Photonics platform.
Keywords: Tapered coupler, III-V epitaxy, SOI wafer, small laser, Si photonics

Novel adiabatic tapered coupler for small III-V lasers grown on SOI wafer


Silicon Nitride PICs Platform Development from a Foundry Perspective: From Concepts to Real Applications
Anton Stroganov, Michael Geiselmann
LIGENTEC SA, Lausanne, Switzerland
e-mail: michael.geiselmann@ligentec.com

ABSTRACT
Silicon Nitride based integrated photonics platforms are going through the stage of fast spread and growth due to many beneficial features such as large transparency window and low propagation losses, presence of Kerr nonlinearity and absence of Two Photon Absorption. To allow integrated photonic devices, the platform capabilities awareness in integrated photonic community and high level of technological maturity are required. At LIGENTEC, we developed the all-nitride-core platform with processes adapted for operation from visible to Mid-IR spectral range and fast fabrication turn-around. Advances and steps towards platform technological maturity from the point of view of a foundry are discussed and demonstrated.
Keywords: Integrated Photonics, Silicon Nitride, High Q Resonators, Low Loss PICs, Hybrid Integration

Silicon Nitride PICs Platform Development from a Foundry Perspective: From Concepts to Real Applications


Recognition of 8QAM Coded Label by Maximum Output of Optical
Waveguide Circuits

Tumendemberel Surenkhorol, Hiroki Kishikawa, Nobuo Goto
Department of Optical Science and Technology, Tokushima University, Tokushima 770-8506, Japan
 c501848002@tokushima-u.ac.jp

ABSTRACT
This research work aims to implement a label recognition function of photonic router in optical domain. A waveguide type circuit has been proposed to recognize label which is considered to be an optical coded signal.
The label can be identified as an unique output ports which have minimum or maximum intensity values. In our previous work, an 8QAM (eight quadrature amplitude modulation) coded label recognition has been analyzed with the minimum output intensities of the circuit. In this paper, the 8QAM coded label recognition is investigated with the maximum output intensities. It is theoretically analyzed and noise tolerance simulation is run.
Keywords: optical 8QAM code, label recognition, optical waveguide circuit, noise tolerance

Recognition of 8QAM Coded Label by Maximum Output of Optical
Waveguide Circuits


Extracting Multiple Parameters from a Compact Circuit for Performance Evaluation Student Paper
Yufei Xing 1; 2; , Mi Wang 1; 2, Alfonso Ruocco 1; 2; 3, Joris Geessels 4, Umar Khan 1; 2, Wim Bogaerts 1; 2
1Photonics Research Group, Ghent University-imec, Ghent, Belgium
2Center of Nano and Biophotonics (NB-Photonics), Ghent, Belgium
3currently at Cambridge Graphene Centre, Cambridge University, Cambridge, UK
4Luceda Photonics, Dendermonde, Belgium
e-mail: yufei.xing@ugent.be

ABSTRACT
We designed a two-stage Mach-Zehnder Interferometer for process monitoring control. Using Restart-CMAES global optimization algorithm, we can extract multiple on-chip waveguide and directional coupler parameters simultaneously. The compact design greatly reduces the footprint and number of measurements and improves accuracy for parameter extraction, making it useful for detailed wafer-level variability analysis.

Extracting Multiple Parameters from a Compact Circuit for Performance Evaluation


Simulation Methodology for LiDAR on Chip
Chenglin Xu1, Evan Heller1, Maryvonne Chalony2
1Synopsys, RSoft Design Group, 400 Executive Blvd, Ossining, NY 10562 USA
2Light Tech, 1128 Route de Toulon, 83400 Hyères, France
e-mail: chenglin@synopsys.com

ABSTRACT
Simulation plays a critical role in the design and optimization of LiDAR on chip, but there is no single software tool that can completely handle such a complex device. In this paper, we present a simulation methodology that decomposes the complex structure into several simpler building blocks, and applies the appropriate algorithm to each. For example, the grating coupler, which is too big for a full FDTD simulation, can be treated through a coherent combination of individual grating simulation results. This provides a feasible solution which can be run on a typical PC.
Keywords: BPM, FDTD, multi-physics, LiDAR

Simulation Methodology for LiDAR on Chip