Power-efficient thermo-optic phase shifters with cavity-SOI

Power-efficient thermo-optic phase shifters have been demonstrated using 3 μm thick silicon on insulator (SOI) waveguides fabricated on cavity-SOI wafers. In cavity-SOI the cavities are premade in the SOI wafer which simplifies the processing of the waveguides with thermally insulated heater structures. Measurement results of asymmetric Mach-Zehnder interferometric TO switches show a 10-fold decrease in required power for α π phase shift in devices fabricated on cavity-SOI when compared to devices fabricated on plain SOI. With the cavities the required heating power for the π phase shift is only 2.1 mW. Numerical simulations support the experimental results.