Coupling-Controlled\nPhotonic Topological Ring Array

Photonic topological insulators with boundary states\npresent a\nrobust solution to mitigate structure imperfections. By alteration\nof the virtual boundary between trivial and topological insulators,\nit is possible to bypass such defects. Coupled resonator optical waveguides\n(CROWs) have demonstrated their utility in realizing photonic topological\ninsulators, as they exhibit distinct topological phases and band structures.\nWith this characteristic, we designed and experimentally validated\na CROW array capable of altering its topological phase by adjusting\nthe coupling strength. This array functions partially as a topological\ninsulator and partially as a topologically trivial array, guiding\nlight along the virtuous boundary between these two regions. By altering\nthe shape of the topological insulator, we can effectively control\nthe optical path. This approach promises practical applications, such\nas optical switches, dynamic light steering, optical sensing, and\noptical computing.