ESE Ph.D. Dissertation Defense: “Non-Hermitian-Driven Photonic Switching––Ultrafast Routing and Robust Power Transfer”

This dissertation explores non-Hermitian control as a unified framework for photonic switching and reconfigurable light routing. First, by harnessing gain–loss modulation and parity–time symmetry breaking in hybrid III–V/silicon platforms, a non-blocking photonic switching architecture is proposed and experimentally demonstrated. The resulting devices exhibit ultrafast switching dynamics, compact footprints, and broadband operation, addressing key limitations of conventional photonic switching platforms. Building on this framework, array-level non-blocking switching and wavelength-selective switching are realized, enabling flexible and programmable multi-wavelength routing. In parallel, this dissertation investigates reconfigurable and robust photonic routing in topological photonic systems enabled by non-Hermitian control. By introducing a hybridized pseudo-spin–flipping coupling mechanism across the interface between two topologically identical domains, tunable and robust power transfer between distinct topological regions is achieved in two-dimensional photonic topological insulators through selective optical pumping. Together, these results establish non-Hermiticity as a powerful and versatile design approach for photonic switching in integrated photonics.