Controlling thermo-optic response in microresonators using bimaterial cantilevers

Abstract

We demonstrate a novel platform to control the thermo-optic sensitivity in nanophotonic devices by evanescent coupling of light with bimaterial cantilevers. The cantilever can be designed to provide a negative thermal feedback to passively compensate for the positive thermo-optic effect in the waveguide core. We demonstrate athermal operation over 14 deg in cantilever coupled Silicon ring resonators, limited only by fabrication tolerances. We also show how the same platform can provide positive thermal feedback and overcome the material thermo-optic limit for increasing sensitivity of resonant detectors and thermal imagers.