polish-the-followingnOur-proposed-tunable-polarization-rotation-device-as-shown-in-Figure-1a-consists-of-SPRS-symmetrical-SPRS-of-the-phase-shifted-arm-where-SPRS-consists-of-a-bi-level-taper-bi-level-taper-Y-branch-3dB-coupler-The-design-of-the-devi

Our proposed tunable polarization rotation device, depicted in Figure 1(a), comprises a symmetrical SPRS of the phase-shifted arm, along with SPRS consisting of a bi-level taper (bi-level taper) and Y-branch 3dB coupler. The device design is SOI-based, with a waveguide layer thickness of 220 nm and a slab layer thickness of 90 nm, and SiO2 cladding layers above and below. The SPRS enables realization of the function of two TE0 beams with equal output phases on input of TE0, and two TE0 beams with a phase difference of π/2 on input of TM0. The device works as follows: when PS is not subjected to voltage, input and output polarization states remain unchanged; when PS voltage is applied to the π/2 phase of one arm, input and output polarization states change. Thus, arbitrary switching between the polarization states of TE0 and TM0 can be achieved by controlling the voltage of the phase shift arm.