Design of nonvolatile and efficient Polarization-Rotating optical switch with phase change material

Abstract

Chalcogenide compound Ge2Sb2Se4Te1 (GSST), an emerging phase change material, features drastic optical property contrast between the amorphous and crystalline states. In this paper, a compact and nonvolatile polarization-rotating optical switch is proposed and demonstrated numerically assisted by a L-shaped GSST waveguide, covering the telecom C- band. The switch exhibits greatly competitive performances with a good trade-off for a low insertion loss below 0.33 dB, a high switching depth (SD) above 34.2 dB, a compact device footprint (length = 4.28 μm) and an operating bandwidth over 100 nm. The device performances with the intermediate states between amorphous and crystalline of GSST are investigated as well. Furthermore, the results show that the optical switch exhibits a satisfactory robustness with SD > 33.8 dB within the ± 20-nm variations for both etching width and height. This work can provide a viable scheme to achieve the functionality of combining polarization rotation and switching, which will simplify the system architecture and improve the integration of polarization diversity circuits for optical routing on chip.