Abstract: Light is a powerful tool for the analysis of chemical and biological species in complex environments. Traditional optical sensors are bulky, costly instruments often involving mechanical moving parts, which severely limits their deployment in practical applications. Photonic integration offers a solution to miniaturize optical sensors into a rugged, chip-scale platform that can be mass produced by using mature microfabrication techniques in the same manner as electronic chips. On-chip integration further provides unprecedented flexibility in implementing novel device designs, which naturally gives rise to the question: What makes the best chip-scale photonic sensor?
In this talk, we provide a detailed account regarding the design rationales of different essential components of a photonic sensing system: the sensing element, the light source, and the light analyzer. Specifically, I start by discussing our recent theoretical work, which resolves a long-standing controversy over the optimal waveguide sensor design. I then introduce digital Fourier transform spectroscopy, a chip-scale spectrometer technology offering superior performance and scalability ideally suited for on-chip photonic sensing. Lastly, I review our work on integration of on-chip supercontinuum sources with waveguide sensors toward a fully integrated, miniaturized spectroscopic sensing system