On-chip non-volatile Sb ₂ Se ₃ electro-optical topological 1 × <i>M</i> switch operating in the THz band

Abstract The evolution toward 6G systems is driven by the need for ultra-high data-rated, low-latency, and reliable terahertz (THz) communications. Topological valley photonics has recently emerged as a robust platform for waveguided THz integrated circuits (TICs), offering advantages in terms of robustness against disorder, fabrication imperfections and negligible bending losses. In parallel, phase change materials enable non-volatile and reversible refractive index modulation, although their integration within THz topological platforms remains largely unexplored. This work presents the theoretical design and simulated performance of novel topological resonant electrically addressed 1 × 2 and 1 × M switches implemented on a silicon photonic–electronic platform and operating at the THz band, specifically around 1 THz and 10 THz. The switching mechanism relies on Sb 2 Se 3 thin film enabling low loss and CMOS compatible programmability, activated through a voltage-controlled graphene Joule heater. Numerical results validate the feasibility of the proposed 1 × 2 switch, representing the first investigation of Sb 2 Se 3 on silicon devices at 1 THz and highlighting their potential for reconfigurable and energy-efficient TICs for future 6G systems.