Electrically Programmable, Low-Loss, Nonvolatile PCM-on-Silicon Photonic Switches Enabled by an ITO Heater

Abstract Electrically programmable nonvolatile photonic switches offer near-zero standby power for reconfigurable photonic integrated circuits but require a low-loss and efficient electrical programming interface. Here, we demonstrate Sb2Se3-on-silicon photonic switches programmed by a transparent indium tin oxide (ITO) microheater with a resistance of ∼74 Ω. Microring measurements show approximately linear length-dependent nonvolatile tuning, with excess-loss coefficients of 0.0013 and 0.012 dB·μm–1 for the amorphous and crystalline states, respectively. A nonvolatile Mach–Zehnder interferometer switch achieves an ∼1 dB insertion loss and a crosstalk below −17.29 dB over 1540–1560 nm. Preliminary quasi-analog programming yields 67 resolvable transmission steps over a tuning range exceeding 18.64 dB under the present measurement conditions. A π/2 phase-biased interferometric design further reduces the required phase swing and phase-change material interaction length. These results establish a proof-of-concept Sb2Se3/ITO electrical programming platform for low-loss nonvolatile silicon photonics, while further optimization of cycling endurance and programming energy is required for robust large-scale programmable photonic circuits.