Transport properties of photonic topological insulators based on microring resonator array

An array of ring resonators specifically designed can perform as a topological insulator. We conduct simulations using both Tight-Binding Model (TBM) and Transfer Matrix Method (TMM) to analyze the transport properties of such optical structure, verifying the presence of robust topological edge states which is immune to disorder and defect. We have also made a comparison between these two methods, of which results suggesting that TBM is only applicable under weakly-coupling condition while TMM is more rigorous. Finally we compared the structure with common microring array and coupled resonator optical waveguide (CROW) to demonstrate that it has desired transmission properties with wide and flat spectral response.