Phase Symmetry Breaking of Counterpropagating Light in Microresonators for Switches and Logic Gates

Abstract The rapidly growing field of integrated photonics is enabling a large number of novel devices for optical data processing, neuromorphic computing and circuits for quantum photonics. While many photonic devices are based on linear optics, nonlinear responses at low threshold power are of high interest for optical switching and computing. In the case of counterpropagating light, nonlinear interactions can be utilized for chip‐based isolators and logic gates. In this work, a symmetry breaking of the phases of counterpropagating light waves is found in high‐Q ring resonators. This abrupt change in the phases can be used for optical switches and logic gates. In addition to these experimental results, theoretical models are provided that describe the phase symmetry breaking of counterpropagating light in ring resonators.