为了减小异面腔四频差动激光陀螺(DLG)腔长变动导致的零漂,对DLG的色散平衡进行了研究。利用气体激光的经典理论,推导了DLG零偏与工作点和轴向磁场的函数关系,给出了色散平衡的理论证明。利用在DLG增益管上缠绕通电线圈,给增益介质施加大小可控的轴向磁场,通过驱动腔平移镜上的压电换能器调节腔长来改变工作点,做出了零偏随腔长和线圈电流的变化曲线。结果表明,零偏对腔长变化的灵敏度是轴向磁场的函数,当增益曲线的塞曼分裂量等于非互易分裂量时零偏对腔长变动不敏感。色散平衡技术减小了腔变动对DLG的影响,有利于提高DLG精度.

In order to reduce drift caused by cavity variation,dispersion equalization of non-planar four-frequency differential laser gyro was investigated. Expression of DLG bias as a function of operating point and axial magnetic field was derived from classic theory of gas laser. Consequently the dispersion equalization was proved theoretically. Coil around gain tube was used to provide axial magnetic field with controllable strength for gain medium,and piezoelectric transducer attached to cavity mirror was used to adjust cavity length or operating point. Afterwards,experimental curve of bias versus cavity length and coil current was obtained. The results showed that bias sensitivity to cavity-length change was a function of axial magnetic field,which was zero with Zeeman splitting of gain curve equal to nonreciprocal splitting. Dispersion equalization reduces drift caused by cavity variation,so it helps to improve DLG precision.