Advanced integrated photonics materials and techniques

High-speed modulators are a fundamental building block of photonic integrated circuits (PICs), but the development of such devices within Si photonics platforms for short wavelengths (< 1000 nm) remains an open challenge. We are investigating thin film lithium niobate (TFLN) electro-optic devices and integration strategies toward submicrometer-wavelength PICs with high-speed modulation capabilities.

Fabrication variation in photonic waveguide dimensions leads to variability in device performance, e.g., in (de)multiplexer channel wavelengths and the bias points of switches/modulators – with short-wavelength devices being especially susceptible. These variations can be offset through active device tuning (at the expense of complexity and power consumption) or trimming (waveguide modification after fabrication). We are developing an in situ thermal trimming method to enable convenient, post-fabrication trimming of packaged PICs. Our method is based on integrated trimming devices and circumvents limitations of previously demonstrated methods (requiring laser/electron beam exposure or additional fabrication steps beyond those of typical Si photonics platforms).

PhD students: Tianyi Liu, Tianyuan Xue

Recent work: