Design of a Multi-Functional Integrated Optical Switch Based on Phase Change Materials

An optical switch based on silicon-on-insulator (SOI) technology is proposed that works in the C-band and switches by amorphous (Am) to crystalline (Cr) and Cr-to-Am phase transitions. The optical switch integrates the functions of polarization beam splitting and mode conversion, and consists of two asymmetric directional couplers (ADCs). The TM0 mode is converted to the TM1 mode through an asymmetric coupler to achieve the polarization splitting of the TM0 mode and TE0 mode. The output of the TE0 mode is then controlled by Ge2Sb2Se4Te1 (GSST). When the TE0 mode is input and the wavelength is 1550 nm, the insertion loss (IL) is lower than 0.62 dB and the crosstalk (CT) is lower than -9.88 dB for a directional coupler loaded with GSST that realizes the optical switch function in both amorphous and crystalline GSST. The extinction ratio (ER) of the two waveguides of the directional coupler is lower than -11.40 dB, simultaneously. When the TM0 mode is input and the wavelength is 1550 nm, the IL is lower than 0.62 dB for a directional coupler loaded without GSST.