Generation and Dynamics of Reconfigurable Kerr Combs via Multimode Self‐Injection Locking

ABSTRACT

Microresonator‐based Kerr combs provide a promising bridge directly linking the microwave and the optical frequency domain, bringing revolutions in optical metrology, spectroscopy, and frequency synthesis. Although self‐injection locking (SIL) has emerged as a powerful technique for Kerr comb generation, existing research mainly focuses on single‐longitudinal‐mode, single‐frequency pump configurations. Here, we present a novel scheme for Kerr comb generation based on multimode SIL, which enables ultralow‐threshold pump power due to high energy concentration inside the microresonator. Besides, combining a fiber laser cavity with a microresonator for multimode SIL realizes reconfigurable Kerr combs with broadband wavelength tunability and dual‐polarization operation. This system also supports switching between a narrow‐linewidth single‐frequency state and a broadband microcomb without auxiliary pumps or active modulation. Furthermore, we systematically characterize the transient dynamics of the Kerr comb through parallel interrogation of multiple comb lines using a highly coherent broadband Fourier domain mode‐locked laser, overcoming limitations of conventional techniques such as high noise, system complexity, and trade‐offs between sampling time and resolution. Our work establishes a new paradigm for reconfigurable microcomb generation and offers an efficient, scalable tool for comb dynamics analysis, contributing to applications in coherent optical communications, encryption, hybrid LiDAR systems, and rapid quantum source characterization.