针对自主研制的Y 型腔正交偏振He-Ne 双频激光器，利用Lamb 半经典理论分析抽运电流、工作点和谐振腔损耗等因素对闭锁阈值频差的影响规律。搭建了Y 型腔正交偏振双频激光器闭锁阈值频差测量系统，从实验上开展对双频激光器闭锁阈值频差影响因素研究。通过改变抽运电流值和公共腔镜上压电陶瓷电压研究抽运电流和工作点对激光器闭锁阈值频差影响。实验结果表明，激光器闭锁阈值频差随抽运电流值增加而减小，工作点越靠近增益曲线中心，激光器闭锁阈值频差越小。当激光器抽运电流值大于2.2 mA 时，调节公共腔压电陶瓷电压至最佳工作点处，激光器闭锁阈值频差可降至几兆赫兹甚至更低。

Based on the Y-shaped cavity orthogonal polarized dual-frequency helium-neon laser, the influences of pump current, operating point as well as the loss of resonator on the locking-threshold frequency difference are analyzed according to Lamb′s semi-classical theory. In order to measure the minimum frequency difference of the Y-shaped cavity orthogonal polarized dual-frequency helium-neon laser, an experimental system is set. Various factors, especially pump current and operating point, are studied in the experiment for the first time. The results show that either the pump current increasing or operating point approaching the gain curve center can cause the minimum frequency difference to decrease. When the pump current value is greater than 2.2 mA with its working state at the optimal operating point, the locking-threshold frequency difference can be less than several MHz.