Generalized Inverse Design of a Compact Thermo-Optic Switch on SOI Platform

We propose and demonstrate a compact thermo-optic switch designed using a generalized inverse design method that decouples the thermal and electromagnetic simulations by first computing the temperature distribution and then incorporating it into the optical optimization process. The inverse-designed device is implemented on a silicon-on-insulator (SOI) platform, where heating induces refractive index changes to achieve optical switching between two output ports. The final structure, with a footprint of only 15 μm×8 μm, achieves an insertion loss of -1.42 dB (unheated) and -1.25 dB (heated, Pheating = 17.56 mW, tresponse time=105μs), crosstalk levels of -28.11 dB and -31.61 dB, and 3 dB bandwidths of approximately 10 nm for the two thermal states. These results demonstrate the effectiveness of inverse design in realizing high-performance, thermally reconfigurable photonic switches, and highlight its potential for future dense and programmable photonic circuits.