Scalable Integration of Phase Change Materials on silicon photonic platform for non-volatile Reconfigurable Photonic Integrated Circuits

Phase change materials (PCMs) have shown significant potential for realizing reconfigurable and non-volatile photonic integrated circuits (PICs). This thesis focused on integrating thin films of the low-loss PCM Sb2S3 with silicon photonic components to enable compact tunable devices. A fabrication process was developed to integrate high-quality Sb2S3 films with SOI waveguides and characterize its reversible amorphous-crystalline phase change. Photonic designs leveraging the pronounced refractive index modulation of Sb2S3 upon phase switching were proposed, including tunable directional couplers and phase shifters with integrated contacts for electrothermal actuation. Short-loop experiments optimized key steps like PCM lift-off and selective etching. Ellipsometry extracted the optical constants of the Sb2S3 films, confirming the refractive index change between phases. Fabrication on SOI was completed to build photonic test structures incorporating Sb2S3 PCM in different configurations. Measurements showed a detectable power shift in PCM-integrated couplers after thermal annealing, indicating photonic reconfiguration. The work establishes a path towards non-volatile Sb2S3 nanophotonic devices, helping address challenges in scaling phase change photonics. Further optimization of designs and processes could enable a new generation of adaptable photonic chips based on phase change integration.