Reconfigurable Free Form Silicon Photonics by Phase Change Waveguides.

The rapid reprogramming of photonic integrated circuits (PICs) offers transformative potential for photonic technologies. Traditional programmable photonic devices, relying on thermo‐optic or electro‐optic effects, face limitations like large size and high energy consumption. Chalcogenide phase‐change materials (CPCMs) have gained attention for enabling energy‐efficient, non‐volatile optical manipulation on‐chip, crucial for in‐memory optical computing. Sb₂S₃ emerges as a promising alternative to conventional CPCMs, providing low loss and reversibility. This work introduces a CMOS‐compatible reconfigurable waveguide platform using Sb₂S₃ thin film on silicon‐on‐insulator (SOI). Laser direct writing enables the creation of complete channel waveguides in a single step, with the flexibility to erase and rewrite segments for rapid design adjustments. The platform demonstrates stable waveguide erasure using a cost‐effective laser engraver and low‐loss coupling between SOI and the phase‐change material‐on‐silicon (PCMoS) waveguide. By combining an economical fabrication process with a robust device architecture, this integration scheme offers a versatile solution for applications such as optical interconnects, neuromorphic and quantum computing, and microwave photonics. [ABSTRACT FROM AUTHOR]