A Self-Injection Locked Laser Based on High-Q Micro-Ring Resonator With Adjustable Feedback

We propose a hybrid integrated self-injection locked (SIL) narrow linewidth laser with adjustable feedback intensity. An adjustable Sagnac loop reflector (ASLR) coupled to a high-
Q
micro-ring resonator is introduced to adjust and optimize the optical feedback intensity of the SIL laser. The experimental results show that the linewidth and tuning performance of the SIL laser are closely related to the optical feedback intensity. After optimizing the reflectivity of ASLR, more excellent frequency noise suppression capability and larger locking range can be obtained compared with the conventional SIL lasers with fixed feedback intensity. The intrinsic linewidth is reduced to 60 Hz, and the locking range without phase compensation is extended to 6.3 GHz. This work has important application value in the field of coherent detection and precision metrology.