Stability in self-injection locking of the DFB laser through a fiber optic resonator

Self-injection locking is an efficient technique to lock the frequency of laser at the resonant frequency of external cavity, which can be used for the all-optical frequency locking of the resonant optical gyroscope instead of the electric frequency locking. However, this technique is very sensitive to the system parameters and environmental disturbances. In this paper, we theoretically and experimentally analyze the dependences of injection ratio, intimal phase delay, operating temperature of distributed feedback (DFB) laser, and the environment temperature disturbance on the stability of self-injection locking. With the DFB laser self-injection locking to a high-Q fiber optic resonator (FOR), the frequency stability achieves less than 100 kHz in 30 min without active electrical feedback.