Low-loss reconfigurable non-blocking optical switching network based on phase change material GSST

Abstract This paper presents a non-volatile optical switch and switch array based on the hybrid integration of silicon waveguides and Ge-Sb-Se-Te (GSST) phase-change material. First, a 2 × 2 optical switch unit is designed by integrating GSST with silicon waveguides, enabling optical path switching by controlling the crystalline/amorphous phase transition of GSST. This switch unit exhibits non-volatile memory characteristics, maintaining its state without a continuous bias voltage, which significantly reduces power consumption and minimizes the footprint on the chip. On this basis, an 8 × 8 and a 16 × 16 optical switching network are constructed by cascading the 2 × 2 switch units according to an optical network topology. Systematic simulation and optimization of the designed 2 × 2 optical switch and array structure show that for the 2 × 2 unit, the insertion loss is 0.098 dB with crosstalk of −15.62 dB in the amorphous state, and 0.047 dB with crosstalk of −10.95 dB in the crystalline state. The expanded 8 × 8 Benes optical switching network maintains good performance, with a total insertion loss of 17 dB in the All-Cross state and 30 dB in the All-Bar state. For the 16 × 16 optical switching network, the total insertion loss is 37.61 dB in the All-Cross state. The proposed low-loss, high-performance optical switch architecture offers an effective solution for realizing large-scale photonic integrated switching networks.