Particle swarm optimized ultra-compact polarization beam splitter on silicon-on-insulator

We have designed an ultra-compact polarization beam splitter on silicon-on-insulator (SOI). The device is designed by a Particle swarm optimized (PSO) inverse-design method with a quite small footprint of 2 × 2 μm2. Simulation results shows that the transmission is 61% for TE mode and 52% for TM mode at designed wavelength 1550 nm. The extinction ratio of our device is greater than 10dB within a bandwidth of 40 nm (1528–1567 nm). Benefiting from the global optimization of our inverse-design method, the transmission and extinction ratio can keep greater than 40% and 10 dB separately for both polarizations when the designed pixel side length varies from 100 to 130 nm. Besides, we demonstrate that the design method could have tolerance for input waveguide width, in this case, the device could maintain functionality while the width of input waveguide ranges from 300 to 350 nm.