Odile Liboiron-Ladouceur

McGill University | McGill · Department of Electrical & Computer Engineering

Integrated silicon photonic devices, which manipulate light to transmit and process information on a silicon-on-insulator chip, are highly sensitive to structural variations. Minor deviations during nanofabrication-the precise process of building structures at the nanometer scale-such as over- or under-etching, corner rounding, and unintended defec...

Mode Division Multiplexing (MDM) is a technique used over the past decade in Silicon Photonics (SiPh) to incorporate more data into communication links by employing higher-order transverse electric or transverse magnetic modes. MDM was primarily used in optical communication; however, in recent years, there have been several applications of MDM in...

This paper presents a microring resonator-based weight function for neuromorphic photonic applications achieving a record-high precision of 11.3 bits and accuracy of 9.3 bits for 2 Gbps input optical signals. The system employs an all-analog self-referenced proportional-integral-derivative (PID) controller to perform real-time temperature stabiliza...

The optical power coupling coefficient serves as a pivotal metric for elucidating mode power distribution within mode group division multiplexers. This paper derives closed-form analytical expressions to calculate the coupling coefficient of Gaussian beams into a graded-index multimode fiber. Leveraging the inherent computational efficiency of anal...

This paper demonstrates the benefits of leveraging free-space optics concepts in the design of certain integrated photonic components, leading to a footprint reduction without compromising on performance. Specifically, we present ultra-short, highly efficient and fabrication-friendly mode-size converters based on metamaterial Fresnel lens-assisted...

Inverse design methodologies effectively optimize many design parameters of a photonic device with respect to a primary objective, uncovering locally optimal designs in a typically non-convex parameter space. Often, a variety of secondary objectives (performance metrics) also need to be considered before fabrication takes place. Hence, a large coll...

This study experimentally demonstrates both inter-chip and intra-chip RF transmission for short-range microwave communication using on-chip antennas, implemented on a silicon photonic platform. The unification of antenna with photonic integrated circuits (PICs) reduces system loss for high data rate communication by eliminating parasitics. We desig...

This work introduces a novel architecture for implementing a parallel coherent photonic digital-to-analog converter (PDAC), designed to transform parallel digital electrical signals into corresponding analog optical output, convertible to analog electrical signals using photodiodes. The proposed architecture incorporates microring resonator-based m...

This paper presents a microring resonator-based weight function for neuromorphic photonic applications achieving a record-high precision of 11.3 bits and accuracy of 9.3 bits for 2 Gbps input optical signals. The system employs an all-analog self-referenced proportional-integral-derivative (PID) controller to perform real-time temperature stabiliza...

We present PreFab, an image-to-image computer vision system that predicts and corrects nanofabrication variations in complex integrated photonic circuits with fine features, enabling higher precision, improved yields, and accelerated development of next-generation photonic technologies.

A novel mode-selective thermo-optic phase shifter (MS-TOPS) enabled by subwavelength grating (SWG) structures is proposed and experimentally demonstrated on a 220 nm waveguide thick silicon photonics chip for the first two quasi-transverse electric modes (TE0, TE1). Mode-selective relative phase manipulation of modes unlocks several processing task...

We demonstrate a novel mesh of Mach-Zehnder interferometers (MZIs) for programmable optical processors. We thoroughly analyze the benefits and drawbacks of previously known meshes and compare our newly proposed mesh with these prior architectures, highlighting its unique features and advantages. The proposed mesh, referred to as Bokun mesh, is an a...

In this work, we experimentally demonstrate a four-mode polarization/mode insensitive 3-dB coupler based on an adiabatic coupler. The proposed design works for the first two transverse electric (TE) modes and the first two transverse magnetic (TM) modes. Over an optical bandwidth of 70 nm (1500 nm to 1570 nm), the coupler exhibits at most 0.7 dB in...

Next-generation integrated nanophotonic device designs leverage advanced optimization techniques such as inverse design and topology optimization which achieve high performance and extreme miniaturization by optimizing a massively complex design space enabled by small feature sizes. However, unless the optimization is heavily constrained, the gener...

We demonstrate a novel mesh of Mach-Zehnder interferometers (MZIs) for programmable optical processors. The proposed mesh, referred to as Bokun mesh, is an architecture that merges the attributes of the prior topologies Diamond and Clements. Similar to Diamond, Bokun provides diagonal paths passing through every individual MZI enabling direct phase...

We demonstrate a novel mesh of interferometers for programmable optical processors. Employing an efficient programming scheme, the proposed architecture improves energy efficiency by 83% maintaining the same computation accuracy for weight matrix changes at 2 kHz.

ML enhances silicon photonics by enabling efficient exploration of complex design spaces and correcting geometrical deviations in fabrication. Our approaches generate optimal designs with better confidence, while reducing calibration runs, saving time and cost.

A novel mode-selective thermo-optic phase shifter (MS-TOPS) enabled by subwavelength grating (SWG) structures is proposed and experimentally demonstrated on a 220 nm waveguide thick silicon photonics chip for the first two quasi-transverse electric modes (TE0, TE1). Mode-selective relative phase manipulation of modes unlocks several processing task...

We demonstrate a novel mesh of interferometers for programmable optical processors. Employing an efficient programming scheme, the proposed architecture improves energy efficiency by 83% maintaining the same computation accuracy for weight matrix changes at 2 kHz.

The performance of integrated silicon photonic devices is sensitive to small structural variations that arise from imperfections in the nanofabrication process. This sensitivity is exacerbated for next-generation devices that require fine feature sizes to push the limits of performance. In this work, we present a deep convolutional neural network m...

Computational inverse design techniques have shown potential to become reliable means for designing compact nanophotonic devices without compromising the performance. Much effort has been made to reduce the computation cost involved in the optimization process and obtain final designs that are robust to fabrication imperfections. In this work, we e...

The integration of optical receivers in nanoscale1CMOS technologies is challenging due to less intrinsic gain2and more noise compared to SiGe BiCMOS technologies.3Recent research revealed that low-noise, high-gain, and low-4power CMOS optical receivers can be designed by limiting5the bandwidth of the front-end followed by equalization tech-6niques...

We design a Multi-Transverse-Mode Optical Processor (MTMOP) on 220 nm thick Silicon Photonics exploiting the first two quasi-transverse electric modes (TE0 and TE1). The objective is to measure the optical phase, required for programming the optical processor, without use of conventional optical phase detection techniques (e.g., coherent detection)...

In this paper, we present the experimental results for integrated photonic devices optimized with an energy-constrained inverse design method. When this constraint is applied, optimizations are directed to solutions that contain the optical field inside the waveguide core medium, leading to more robust designs with relatively larger minimum feature...

To mitigate the trade-off between gain and bandwidth of CMOS multistage amplifiers, a receiver front-end (FE) that employs a high-gain narrowband transimpedance amplifier (TIA) followed by an equalizing main amplifier (EMA) is proposed. The EMA provides a high-frequency peaking to extend the FE’s bandwidth from 25% to 60% of the targeted data rate...

A three-channel (de)multiplexer with 50 nm channel spacing and 6.2 μm × 5.4 μm footprint is designed with an energy constrained inverse design method, providing low loss, acceptable crosstalk, and 47 nm 3-dB bandwidth experimentally.

This article explores the power-sensitivity trade-off in optical receivers aiming to improve the energy-efficiency of the overall link. Optical receivers with field-effect transistor (FET) front-ends (FEs) are usually designed for optimal noise performance by matching the circuit’s input capacitance ( C_I ) to the total input parasitic ca...

We report on a low-loss (<1dB) TE1-TE3 mode converter, robust to ±10 nm etch-errors, operating over a wavelength range of 1.5-1.58 μm with modal crosstalk below -20dB. 20 GBaud PAM-4 signal transmission validates the conversion.

We design a Multi-Transverse-Mode Optical Processor (MTMOP) on 220 nm thick Silicon Photonics exploiting the first two quasi-transverse electric modes (TE0 and TE1). The objective is to measure the optical phase, required for programming the optical processor, without use of conventional optical phase detection techniques ( e.g. , coherent detecti...

This chapter presents the background principles of multiport programmable optical processors which are a mesh of 2 × 2 reconfigurable Mach-Zehnder interferometers (MZIs) in different topologies. It demonstrates how the unitary transformation matrix of a given application is decomposed for programming such MZI-based optical processors. Additionally,...

The multimode characteristics of vertical cavity surface emitting laser (VCSEL) sources lead to mode partition noise (MPN) impairing high-speed multimode fiber (MMF) links. In this letter, we propose a low-cost and straightforward MPN mitigation scheme by optimizing the launch condition between the VCSEL and the MMF. The dependence of the MPN on la...

In this paper, we derive the closed-form analytical expressions of the power coupling coefficients for a Laguerre-Gaussian beam coupled into a graded-index fiber with either central, offset, or tilted launch. We further generalize to an arbitrary launching condition with the radial offset and the three-dimension angular tilt simultaneously occurrin...

The multimode power splitter is a fundamental component in mode-division multiplexed systems. In this paper, we design and characterize a broadband compact dual-mode multimode interferometer (MMI) optical power splitter based on subwavelength grating (SWG) structures. The optimized dual-mode MMI is three times more compact than its conventional mod...

Reconfigurable linear optical processors can be used to perform linear transformations and are instrumental in effectively computing matrix–vector multiplications required in each neural network layer. In this paper, we characterize and compare two thermally tuned photonic integrated processors realized in silicon-on-insulator and silicon nitride p...

In a development towards high-radix datacenter networks, we demonstrate 25 GBaud PAM4 transmission through a three-stage 8 × 8 SOA-based lossless optical switch, implemented as a monolithic photonic integrated circuit in indium phosphide.

We propose and experimentally demonstrate a novel design approach for scalable 3-port and 4-port mode insensitive multimode switching matrices for the first two quasi-transverse electric (TE) modes. The mode insensitive phase shifter ensures less power consumption for simultaneous multimode signal transmission in a mode division multiplexing (MDM)...

In this paper, we introduce an energy constraint to improve topology-based inverse design. Current methods typically place the constraints solely on the device geometry and require many optimization iterations to converge to a manufacturable solution. In our approach the energy constraint directs the optimization process to solutions that best cont...

A 4 4 reconfigurable Mach-Zehnder interferometer (MZI)-based linear optical processor is investigated through its theoretical analyses and characterized experimentally. The linear transformation matrix of the structure is theoretically determined using its building block, which is a 2 2 reconfigurable MZI. To program the device, the linear transfor...

We investigate the monolithic integration of RF antennas onto a silicon-based integrated microwave photonics (IMWP) chip for short-range millimeter-wave (mmW) communication. The unification of antenna with photonic integrated circuits (PICs) reduces system loss for high data rate communication by eliminating parasitic interconnects. This integratio...

In this paper, we design and experimentally demonstrate a two-mode and three-mode mode exchanger (ME) using inverse design method. The designed MEs provide more flexibility for mode division multiplexing (MDM) system links. The optimized designs are compact, 16 m² and 24 m² for the two-mode and three-mode ME, respectively. Dur...

We present spectral-dependent electronic-photonic modeling of vertical-cavity surface-emitting laser (VCSEL)-multimode fiber (MMF) links for next-generation high-speed interconnects. The beam coupling processes, between the VCSEL and the MMF and between the MMF and the photodetector (PD), are discussed, with spectral-dependent three-dimensional lau...

A mesh of interferometers can be arranged to route an optical signal or linearly transform an optical input vector. The talk discusses how Mach-Zehnder based switches became key in optical processors.

A 16×16 SiPh thermo-optic switch provides 100 nm of bandwidth, at most 8 dB in crosstalk, and 3.8 dB loss for the longest path. At 10 Gb/s, this energy-efficient switch consumes less than 7 pJ/bit.

A tilted-beam-enabled optical equalization scheme efficiently extends the VCSEL-MMF channel bandwidth. A proof-of-principle PAM-4 transmission over MMF shows a 60% power penalty improvement over a conventional central launch.

Physics-guided formulation leads to more efficient inverse designs at lower computation costs. We validate this design approach with the performance analysis of mode converters and mode division multiplexers having efficiencies above 96% at 1.55 μm.

This paper discusses motivations and challenges behind the online transition of the Montreal Photonics Networking event. Design, organization strategies, and outcomes of this educational and community-focused activity are presented.

We design and experimentally demonstrate scalable 2 × 2, 4 × 4 and 8 × 8 silicon photonic (SiPh) thermo-optic switch exhibiting low loss, low crosstalk, low power penalty, and BER below 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> for payload data transmission. Less than 3.13 dB inserti...

This article presents the implementation of a novel 22-Gb/s energy-efficient optoelectronic receiver architecture in 65-nm CMOS for short-reach optical communication. The receiver incorporates four sub receivers with a two-bit integrating resettable front-end in each sub receiver. The inputs to two of the four sub receivers are optically delayed by...

Mach Zehnder Interferometer-based reconfigurable structures are promising candidates for fast and power-efficient computations in optical neural networks. This work presents the classification performance analysis of a single layer optical neural network implemented by Reck and Clements meshes in the presence of experimental imperfections.