Controllable topological excitation transmission and topological router in an asymmetric splicing Su-Schrieffer-Heeger chain

We propose a scheme to implement controllable and robust excitation transmission through topological edge channels in an asymmetric splicing Su-Schrieffer-Heeger chain. We realize two modes of controllable excitation transmission behaviors, including flexible selection of input ports and bidirectional switching at the output ports. Especially, variations in the asymmetric chain coupling configurations support topological excitation to be injected from tunable multiple input ports. By introducing on-site potentials at both ends, we break chiral symmetry, and distinctive transmission channels are opened. The topological excitation can be transferred from the interface to either edge by tuning the strength of on-site potentials while maintaining robustness against disorder perturbations. Consequently, the excitation transmission with two paths can be regarded as a bidirectional topological switch. Furthermore, we construct a four-chain cross-linking model to achieve a topological router with a tunable number of output ports. We also explore the experimental feasibility of achieving controllable excitation transmission in an optomechanical array. Our scheme opens an innovative avenue for investigating topological photonics and facilitating their future application for topological quantum devices.