Mirror-Assisted Self-Injection Locking of a Laser to a Whispering-Gallery-Mode Microresonator

Self-injection locking is a dynamic phenomenon, which provides passive stabilization of a laser emission frequency via resonant optical feedback. The stabilization coefficient depends on the level of the feedback and quality factor of the external resonant structure creating the feedback. A conventional self-injection locked laser (SIL) based on a dielectric cavity involves barely tunable resonant Rayleigh scattering (RRS). In this work we study theoretically a scheme of a SIL via a high-Q microresonator with a drop-port coupled mirror, in which the optical feedback level is optimally adjusted by tuning the dropport mirror coupling. We show that the additional reflector can improve the laser stabilization and power handling efficiency if compared with the classic RRS-based scheme.