Reconfigurable topological phases in next-nearest-neighbor coupled resonator lattices. (arXiv:1802.02253v1 [physics.optics])

We present a reconfigurable topological photonic system consisting of a 2D
lattice of coupled ring resonators, with two sublattices of site rings coupled
by link rings, which can be accurately described by a tight-binding model.
Unlike previous coupled-ring topological models, the design is translationally
invariant, similar to the Haldane model, and the nontrivial topology is a
result of next-nearest couplings with non-zero staggered phases. The system
exhibits a topological phase transition between trivial and Chern insulator
phases when the sublattices are frequency detuned. Such topological phase
transitions can be easily induced by thermal or electro-optic modulators, or
nonlinear cross phase modulation. We use this lattice to design reconfigurable
topological waveguides, with potential applications in on-chip photon routing
and switching.

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