Defect-enhanced silicon photodiodes and modulators for photonic integrated circuits

Dr. Dylan Logan

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Photonics)

Abstract:

Silicon photonics is a probable candidate to alleviate the bottleneck faced in data transfer between and within integrated circuits, by employing optical signal transmission on CMOS-compatible silicon devices. A fundamental difficulty however is faced in simultaneously achieving low-loss optical transmission and optical-to-electric conversion on the same silicon substrate. One approach is to enhance local absorption for sub-bandgap wavelengths by incorporating lattice defects that have deep-level energy states within the silicon bandgap. This seminar will describe the physics governing the defect-enhanced process, and illustrate several fabricated device structures targeted for different areas in a transceiver circuit. Specifically, the integration of the photodiode with other optical elements will be used to exemplify suitable applications for silicon photonic s. In addition, the use of deep levels to enhance the modulation of light in silicon waveguides will be demonstrated.

Biography:

Dylan Logan received his B. Eng. and Ph.D. in 2007 and 2011 respectively, with the Department of Engineering Physics at McMaster University. He was the recipient of the NSERC Canada Graduate Scholarship (CGS) for his Ph. D. work, where he primarily studied silicon photonic waveguide photodetectors and modulators. His thesis, titled 'Defect-enhanced silicon photodiodes for photonic integrated circuits,' explored the use of ion implantation-induced lattice defects to integrate photodetectors onto silicon waveguides operating at 1550 nm wavelength. During his graduate studies, he spent one year as a guest researcher at the University of Glasgow, where he used the electron-beam lithography tools to fabricate ring resonator-based silicon photodiodes.  He is currently a Postdoctoral Fellow with Professor Helmy's photonics group, and is studying applications of nonlinear optical phenomenon and mode conversion in Bragg reflection waveguides.