Compact reconfigurable on-chip polarization beam splitters enabled by phase change material.

In this paper, we present the design of a compact reconfigurable polarization beam splitter (PBS) enabled by ultralow-loss phase-changing Sb2Se3. By harnessing the phase-change-mediated mode coupling in a directional coupler (DC), guided light with different polarizations could be routed into different paths and this routing could be dynamically switched upon the phase change of Sb2Se3. With an optimized DC region, the proposed PBS demonstrates efficient polarization splitting with crosstalk less than -21.3 dB and insertion loss less than 0.16 dB at 1550 nm for both phase states of Sb2Se3, and features energy efficient property benefitting from the nonvolatile phase change of Sb2Se3, which holds great potentials for on-chip applications involving polarization control, including polarization-division multiplexing system, quantum photonics, microwave photonics, etc.