Design optimization for micromachined low power Mach-Zehnder thermo-optic switch

Abstract
The main issue of a Mach-Zehnder interferometer based thermo-optic switch is that it needs large heating power to get adequate phase shift for switching. A device structure of etching in a silicon groove underneath the heated arm of waveguide was to suppress the heat loss through the bulk silicon substrate, hence reducing the required heating power. This study shows that the optimum design of the device is obtained when the silicon etched groove is located asymmetrically with respect to the two waveguide branches; power consumption as low as 49mW and fast response time of a few milliseconds can be achieved.