Optimization of a silicon-on-sapphire waveguide device for optical bistable operation

Abstract

A silicon-on-sapphire waveguide is studied theoretically and experimentally in a pulsed regime to obtain bistable operation. Very fast switchings can be observed and are explained as a result of the competition between electronic and thermal nonlinear effects. Pseudobistable operation is demonstrated when the electronic effects are favored, owing to an increase in the silicon photogenerated electron–hole pair lifetime or to a reduction in the incident pulse duration. Other factors such as the grating-coupler efficiency and the sample thermalization can, likewise, improve the device operation.