Compact nonvolatile polarization switch using an asymmetric SbSe-loaded silicon waveguide.

We propose and simulate a compact (∼29.5 µm-long) nonvolatile polarization switch based on an asymmetric SbSe-clad silicon photonic waveguide. The polarization state is switched between TM and TE mode by modifying the phase of nonvolatile SbSe between amorphous and crystalline. When the SbSe is amorphous, two-mode interference happens in the polarization-rotation section resulting in efficient TE-TM conversion. On the other hand, when the material is in the crystalline state, there is little polarization conversion because the interference between the two hybridized modes is significantly suppressed, and both TE and TM modes go through the device without any change. The designed polarization switch has a high polarization extinction ratio of > 20 dB and an ultra-low excess loss of < 0.22 dB in the wavelength range of 1520-1585 nm for both TE and TM modes.