通过理论分析，得到了掺铒光纤环形腔激光陀螺中存在后向反射时，陀螺的两束激光频差和陀螺转速动态关系的解析表达式,并用矢量图明确表明了闭锁效应出现的条件。分析表明光纤激光陀螺的闭锁主要是由瑞利后向散射引起的，这一散射虽然在红外波长甚弱，但在有源环形腔内会被显著加强，因此成为陀螺闭锁的主要原因。实验证实了上述理论分析结果，在陀螺旋转速度小于10° /s时出现了闭锁。

Taking account of the backscattering in a ring cavity, resonance behavior of two counter-propagating lasing beams is analyzed and the dynamic lasing frequencies as a function of rotation rates are obtained in a close form. The condition for occurring lock-in effect in the gyro is also obtained easily from the vector diagrams. It is noted that the Rayleigh backscattering is the main source to form the lock-in effect, although the scattering is weak in a fiber at infrared wavelength, which can be considerably enhanced in an active resonator. The above mentioned analytic close form of dynamic frequencies is confirmed by a fiber ring laser gyro experiment, and the gyro is locked-in when its rotation rate is less than 10° /s.