Nonvolatile and Low‐Loss Reconfigurable Optical Switches Using Sb ₂ S ₃ Phase Change Material

For developing effective reconfigurable photonic devices, low‐loss phase change materials, such as Sb 2 S 3 , can be a good choice. Sb 2 S 3 ‐tunable directional couplers (DCs) have the lowest insertion loss in both amorphous and crystalline states. However, they suffer from a large coupling length issue, which can be overcome by combining with hybrid plasmonic waveguides (HPWGs). Herein, a Sb 2 S 3 ‐assisted HPWG‐based reconfigurable, nonvolatile 1 × 2 switch that has been designed using an asymmetric DC is proposed. The proposed switch has dual‐polarization functionality (operates in both transverse electric and TM modes) indicating its broader applicability and flexibility in integrated photonic systems where polarization diversity is often required. The optical characteristics and coupling behavior with phase transitions have been numerically examined. With a compact coupling length of 46 μm, the proposed 1 × 2 switch achieves a low insertion loss of ≈0.5 dB and a small crosstalk of <−10 dB over a bandwidth of 70 nm (1510–1580 nm).