Nanophotonic optical gyroscope with sensitivity enhancement around "mirrored" exceptional points

Unavoidable thermal fluctuation and fabrication error severely compromise the sensing performance of nanophotonic optical gyroscope devices in practice. In this paper, we theoretically propose a doubly-coupled-ring gyroscope system that not only takes advantage of exceptional point enhanced rotation sensitivity but also improves the robustness against thermal fluctuation and fabrication error. In the doubly-coupled-ring gyroscope with gains, two mirrored exceptional point supermodes experience opposite responses to rotation but same response to thermal fluctuation and fabrication error. Thus, differential readout of the frequency splitting from the two mirrored exceptional point supermodes results in a nearly 100% common-mode noise rejection and remarkably enhances the measurement precision and sensitivity of the photonic optical gyroscope. The proposed doubly-coupled-ring system is a promising platform for not only the novel photonic optical gyroscope but also the next-generation exceptional point sensor in general.