A High Extinction Ratio Silicon Thermo-Optic Switch With Variable Splitter and Spiral Phase Shifters

We designed and fabricated a high extinction ratio silicon Mach-Zehnder thermo-optic switch with variable splitter and spiral phase shifters. The proposed TO switch can achieve high extinction ratios over 38 dB from 1520 nm to 1580 nm for both bar-port and cross-port with maximum value over 45 dB around 1560 nm. In addition, the proposed silicon thermo-optic switch can achieve lower power consumption than the conventional thermo-optic switch on the same chip and is extremely tolerant to the power imbalance of the MMI 3-dB splitter. This proposed silicon thermo-optic switch has great potential for large scale integration applications.