Low-polarization-sensitivity high-speed optical switch on the 220-nm silicon-on-insulator platform

To ensure high-fidelity signal switching, the optical switches should handle incoming signals with random polarizations. In this paper, we demonstrate a 2 × 2 low-polarization-sensitivity high-speed Mach-Zehnder interferometer (MZI) optical switch on the 220-nm-thick silicon-on-insulator (SOI) platform using a standard multi-project wafer (MPW) process. The optical switch incorporates two polarization-insensitive 3-dB splitters based on quasi-adiabatic coupling, along with two polarization-insensitive high-speed phase shifters based on PIN-diode actuated ridge waveguides. The fabricated optical switch features an insertion loss of 0.92/2.79 dB and a switching speed of 52.2/55.0 ns for TE₀/TM₀ mode at the 1550 nm wavelength. The optical switch, with its high speed and CMOS compatibility, can be further optimized and scaled to accommodate the demands of large-scale, high-speed, polarization-insensitive, and high-fidelity switching for supporting AI applications.