Abstract

Topological photonic insulators (TPIs) have attracted considerable attention due to their unique ability to transport light via topologically-protected edge states that are immune to defect scattering [1]. Among the various possible implementations of TPIs, coupled microring resonator lattices have been shown to be a versatile platform for realizing Floquet topological insulators [2,3]. However, most works to date have focused mainly on the unique properties of the topologically-protected edge states [2,3,4] while very little attention has been paid to exploring the bulk mode properties of these lattices for potential applications. In this paper, we report a new optical resonance phenomenon in which light is trapped and stored in the localized bulk modes of a Floquet TPI microring lattice. We show that this “bulk mode resonance” arises from the topological behaviour of the lattice, does not require a physical cavity and can be excited deep in the bulk through nonlocal interactions.

© 2019 IEEE