Broadband Polarization-Insensitive Thermo-Optic Switches on a 220-nm Silicon-on-Insulator Platform

We demonstrate a polarization-insensitive 2 × thermo-optic switch on 220-nm silicon-on-insulator platform. This device is based balanced Mach-Zehnder interferometer with arms consisting of square-cross-section waveguides. In simulations, the (MZS) exhibits extinction ratios (ERs) > 9.5 dB for transverse electric (TE) and magnetic (TM) polarized modes from 1500 nm to 1600 nm. Experimental results verify broadband operation MZS: switching two polarizations ERs 10 over an 85-nm wavelength range. Across C-band (1530 $\sim$ 1565 nm), fabricated MZS has insertion losses 0.2 4.3 16 (14 dB) at cross (bar) port both TE TM polarizations. The polarization-dependent are around within 100-nm range, showing low polarization diversity MZS. proposed promising building block implementing on-chip polarization-division-multiplexed optical interconnects.