Lattice dislocation in a photonic weak topological insulator with a synthetic frequency dimension

Abstract

We propose realization of photonic 3D topological insulator in a 2D microring array with a synthetic dimension along the frequency axis. We show that by modulating only a few rings, we can create a screw dislocation in the 3D topological insulator which supports a protected one-way state localized on the dislocation line.