Asymmetric Topological Valley Edge States on Silicon‐On‐Insulator Platform

Abstract

Abstract Valley‐Hall photonic topological insulators (VPTIs) provide an intriguing approach to suppress backscattering, enhance the robustness of transport, and shrink the footprints of the topological devices. However, previous works focused on the transmission characteristics of the symmetric topological waveguides with few reports on functional devices involving edge mode coupling, which hinders the implementation of various functional devices such as optical couplers/splitters, switches, filters, and etc. In this paper, a new method to manipulate the mode field distributions in topological waveguides is demonstrated by introducing asymmetric edge states, thus the mode coupling with an arbitrary coupling ratio can be achieved between topological waveguides. As an example, a topological power splitter with a 33:67 splitting ratio is demonstrated experimentally. In addition, to verify the robust transmission property of the topological photonic devices, a high‐speed data transmission experiment for a topological power splitter is performed and a high data rate of 128 Gb s −1 is achieved. These results promise a new method to manipulate the mode field distribution in topological waveguides and devices that may find wide applications in diverse fields such as optical communications, nanophotonics, and quantum information processing.