Research Progress of Microresonator-Based Optical Frequency Combs

Optical frequency combs arc composed of a series of discrete and equidistant coherent lasers. Optical frequency combs can be used as a high-precision optical frequency scale for accurate measurement of time and frequency. In recent years, microcavity-generated optical frequency combs have attracted significant attention due to their compact footprint, low power consumption, and monolithic integration. The emergence of solitons greatly improves the coherence of microcavity optical frequency combs that arc characterized by rich nonlinear physical dynamics and have good application prospects in optical clocks, ultrafast measurements, coherent communication, and other fields. In this article, recent progress of microcavity optical frequency combs is reviewed. Specifically, the theoretical models, generation methods, physical mechanisms, characterizations, and applications of microcavity optical frequency combs arc considered. Future trends and perspectives arc also discussed. Soliton microcavity optical frequency combs have been considered outstanding candidates in the exploration of next generation optical sources and arc expected to lead to revolutionary developments in various fields.