Non-volatile reconfigurable planar lightwave circuit splitter enabled by laser-directed Sb₂S₃ phase transitions

Planar lightwave circuit (PLC) splitters have long been foundational components in passive optical communication networks, achieving commercial success since the 1990s. However, their inherent fixed splitting ratios impose significant limitations on capacity expansion, often requiring physical replacement and causing service disruptions. Thermally tunable optical splitters address this challenge by enabling adjustable splitting ratios, but their operation is contingent upon a continuous power supply and complex driving systems. In this work, we present a novel, non-volatile tunable PLC platform based on Sb₂S₃ phase-change materials. The proposed device, which incorporates a Mach-Zehnder interferometer (MZI) optical switch structure, offers tunable splitting ratios via laser-direct writing or ohmic heating, providing flexible reconfiguration capabilities. Experimental results demonstrate non-volatile power splitting ranging from 50∶50 to 20∶80, with a modest increase of approximately 1 dB in additional loss. This work highlights the potential of the proposed platform for low-power, high-efficiency, and reconfigurable photonic networks.