建立了Y型腔正交偏振激光器光强调谐实验系统，通过改变非共用腔腔镜上的压电陶瓷电压来改变分裂频差，通过改变共用腔腔镜上压电陶瓷电压实现共用腔调谐。报道了不同分裂频差下共用腔调谐过程中激光器的光强调谐曲线和相应的拍频变化曲线。采用三阶微扰近似下的兰姆半经典气体激光器理论，较为全面地分析和总结了影响光强调谐规律的各种因素及影响机理。理论分析表明在采用氖双同位素的Y型腔正交偏振激光器内，纵模的单程损耗、单程增益、相邻纵模间的分裂频差等因素通过光强的自洽方程影响纵模竞争的强弱及竞争结果。总结了不同频差下的光强调谐和拍频变化规律，并对其进行了理论分析与解释。

Output power tuning experimental setup of Y-shaped cavity orthogonal polarized He-Ne laser is built. The mode split frequency difference is changed through changing voltage applied on the end mirror of S sub-cavity (or P sub-cavity), while the common cavity′s length is tuned with the voltage applied on the end mirror of the common cavity varied. It is reported that the light power tuning curves and their beat frequencies variation tune in the cases of different mode split frequency difference with common cavity. Based on the Lamb semiclassic gas laser theory of three-order perturbation, influencing factors and their mechanism are investigated and generalized detailedly. Theoretical analysis shows that longitudinal modes loss, gain per pass and their frequency difference affect the pattern and result of mode competition, which obey the self-consistent equations of light intensity. In the end the light power tuning curves and beat frequencies variation of different frequency difference are theoretically analyzed and explained.