Thermal Control Of Nanophotonic Structures: Towards Low Power Optical Interconnects And Energy Applications

Abstract

This thesis explores the interplay between temperature and nanophotonics. In the beginning of the thesis, we address the problem of thermal stabilization of silicon photonic devices, which is a major obstacle in low power integration of on-chip optical interconnects. We demonstrate different schemes, at architecture and device levels, to mitigate thermal sensitivity in optical devices. Using one of the schemes, we demonstrate a ring resonator based electro-optic modulator working over 40 degrees. All the athermal schemes are passive and CMOS- compatible, making them more attractive over active feedback based power- hungry techniques. The latter part of the thesis explores photon-based radiative heat transfer processes. Conventional blackbody radiation is much weaker than solid-state phonon based heat transfer, but its spectrum can be tailored easily as opposed to broadband nature of phonons. Near-field thermal radiation provides a way to overcome the traditional blackbody limit by increasing radiative density of states. We use this phenomenon to demonstrate strong near-field cooling of a thermally isolated membrane through evanescent coupling with a tip. Finally we demonstrate thermal rectification by using temperature dependent spectral properties in a radiative channel.