The lock in effect and threshold expressions caused by backscattering from cavity mirrors in a passive resonator gyroscopy are derived based on the resonance characteristics of cavity.

• 从谐振腔的谐振特性出发，严格地推导出无源谐振腔激光陀螺中由腔镜背散射引起的闭锁效应关系式及闭锁阈值表达式。