Effects of backscattering in high-Q, large-area silicon-on-insulator ring resonators

We demonstrate large-area silicon-on-insulator ring resonators with Q values of about 2×10⁶ at critical coupling and 3.6×10⁶ for heavily undercoupled conditions. A model has been developed to understand the impact of waveguide backscattering and subcomponent imperfections on the spectral response of our devices. The model predicts the appearance of signals at ports that would not have them under backscattering-free, ideal-power-splitting conditions. The predictions of our model are shown to match the phenomena observed in our measurements.