Topology Optimization of Efficient and Compact Thermo-Optical Phase Shifters

Thermo-optical phase shifters (TOPSs) have emerged as an important building block in silicon photonics platforms due to their ability to dynamically control the optical phase of light. To enable wide-scale adoption in practical applications, it is paramount that TOPSs are optimized for low power consumption, low optical loss, small footprint, small thermal time constant, and easy fabrication, among other ideal characteristics. In the last decades, multiple designs have emerged from intuition and trial-and-error-based processes to match these objectives. In this work, we propose a topology optimization-based multiphysics inverse design framework for designing cross-sectionally compact low-optical-loss TOPS devices that can accommodate fabrication constraints. Results demonstrate the capability of tailoring novel designs with losses up to 33% lower than previously proposed designs.