Research

We currently have three research themes: Silicon photonics, vanadium dioxide nanophotonics, and neurophotonics.

1. Silicon Photonics

The field of silicon (Si) photonics aims to form photonic devices and circuits on Si substrates using the manufacturing infrastructure of CMOS electronics. The large Si substrates and wafer-scale microelectronic packaging lead to high production volumes that can reduce the cost of an optical chip.  We access foundry services and collaborate with world-leading teams to realize a variety of active and passive Si photonic devices and circuits for applications in communications.

Our main topics of research are:

SiN-on-Si Multilayer Photonic Platforms

Optical Modulators

Multi-Variable Control


Bi-level passive platform; Tri-level active platform (ongoing)
Coupling modulated microrings; PN junctions for efficient microrings and MZIs; GeSi EAMs (ongoing)
Automatic initialization and stabilization of large-scale photonic devices and circuits (ongoing)

Optical IO and Polarization Control

III-V-on-Si Hybrid Integration

Photonic Circuits & EO Integration

Bi-level grating couplers for broadband and efficient fiber-to-chip interfaces; Polarization rotator splitters and controllers VCSEL integration; hybrid Si lasers (ongoing)
Quantum key distribution transmitter (with Prof. H.-K. Lo); 44Gb/s 3D-integrated EO transmitter (with Prof. S. Voinigescu)

2. Vanadium Dioxide Nanophotonics

Vanadium dioxide (VO2) exhibits a reversible insulator-metal transition (IMT) that can be initiated thermally (near 67oC), by carrier injection, or optically. We have completed a number of studies on the electrically-induced IMT of VO2 and have learned to form devices from the material. Accompanied with the large resistivity change across the IMT is a refractive index change of order unity, which enables the realization of very thin and/or miniaturized optoelectronic devices.

Our recent topics of research* are:

*In collaboration with S. Paradis and D. Alain (DRDC-Valcartier), and Prof. R. Haglund (Vanderbilt University)

3. Neurophotonics

We are bringing our expertise in foundry integrated photonics to create new nano-tools to study and navigate the brain. Much remains unknown about the complex and dense connectivity among the neurons in the brain. Developments in optogenetics, optical reporters, and two photon imaging are revolutionizing how light can be used to study neural connectivity. Learning about neural circuits will enable us to have a deeper understanding of the "mind" (e.g., memory, learning, perception, emotion, behaviour, consciousness).  This knowledge can lead to new types of compute technologies as well as help us identify the causes of and possible treatments for neurological, psychiatric, and cognitive disorders.

We are part of the Neurotech Alliance: http://neuronano.org/

Nanophotonic Neuroprobes

Optical Coherence Tomography


Massively parallel brain activity mapping Ex vivo, in vivo, and clinical deep brain imaging

In collaboration with Prof. M. Roukes (Caltech)
In collaboration with Prof./Dr. A. Lozano, Dr. Y.-S. Senova (U of T, Toronto Western Hospital)