Figure 10.

(top) A broadband $2\times 2$ silicon photonic switch based on GST and doped silicon PIN heaters

Adapted from Chen, Rui et al. “Broadband Nonvolatile Electrically Controlled Programmable Units in Silicon Photonics.” ACS Photonics 9.6 (2022): 2142–2150. (bottom) A low-loss phase shifter based on Sb₂Se₃ controlled by a graphene heater. Adapted from Fang, Zhuoran et al. “Ultra-low-energy programmable non-volatile silicon photonics based on phase-change materials with graphene heaters.” Nature Nanotechnology 17.8 (2022): 842–848.