Asymmetric frequency multiplexing topological devices based on a floating edge band

• DOI: 10.1364/prj.518426
• Publication Date: 2024-03-20T18:00:09Z
• Authors: Jiajun Ma; Chunmei Ouyang; Yuting Yang; Dongyang Wang; Hongyi Li; Li Niu; Yi Liu; Quan Xu; Yanfeng Li; Zhen Tian; Jiaguang Han; Weili Zhang
• Keywords: Topological insulator; Frequency-division multiplexing

Topological photonics provides a platform for robust energy transport regardless of sharp corners and defects. Recently, the frequency multiplexing topological devices have attracted much attention due to ability separate optical signals by wavelength hence potential application in communication systems. Existing are generally based on slow light effect. However, resulting static local spatial mode or finely tuned flat band has zero-group velocity, making it difficult both experimental excitation channel out-coupling. Here, we propose experimentally demonstrate an alternative prototype asymmetric including rainbow router floating edge (instead localized ones); multiple channels can be collectively excited with point source efficiently routed output ports. The separation our design is achieved gradually tuning gap truncation over wide range frequencies. A crucial feature lies that detached from bulk states within upper lower photonic gaps. More interestingly, sandwiched morphology band, top bottom gaps will each truncate into support propagation towards opposite directions, asymmetrical transportation realized devices.