  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 spin 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.

Optics;Mesoscale and Nanoscale Physics;Quantum Physics