Programmable photonic integrated circuits (PPICs) promise multifunctional, generic photonic chips, but most existing demonstrations rely on thermo-optic tuning, which is volatile and power hungry, limiting scalability. Phase-change materials (PCMs) offer a compelling alternative because of their zero-static-power operation and large refractive-index contrast, enabling ultra-low-energy and ultra-compact PPICs.

In this talk, I will present key PCM-enabled building blocks developed on silicon photonics, including optical switches and phase shifters. To demonstrate scalability, we collaborated with Intel’s 300 mm silicon photonics fab and achieved precise, multibit, low-loss tuning of Sb₂Se₃ using a closed-loop program-and-verify approach. Electrically reconfigurable PCM-integrated gates were then implemented in both circulating and forward Mach-Zehnder interferometer meshes. These platforms enable broadband optical switching, high-Q coupled resonators with local coupling control, and optical mode sorting.

I will also present active metasurfaces based on guided-mode resonance and a thin layer of Sb₂Se₃. Using doped silicon nanowire heaters, we demonstrated an individually addressable transmissive metasurface with deterministic multilevel switching, full 2π phase modulation, and tunable far-field beam shaping. Together, these results establish scalable, zero-static-power programmable photonic systems spanning both integrated photonics and active metasurfaces.