光学参量过程是产生压缩光的关键环节，为了提高实验中光学参量振荡腔的稳定性，必须将激光与光学参量振荡腔进行模式匹配，并用锁定技术稳定光学参量振荡腔。理论分析了模式匹配效率对压缩度和偏频锁定技术精度的影响。经过模式匹配之后，在实验上实现了光学参量振荡腔的锁定，并对锁定后的光学参量振荡腔进行了稳定性测量。理论与实验结果表明：模式匹配效果越好，压缩光的压缩度和偏频技术的锁定精度越高；在较好的模式匹配条件下，光学参量振荡腔的腔长锁定精度为7.35 nm，稳定时间可达2 h以上，能够满足对压缩态光场的探测需要。

Optical parametric oscillation is the critical part in the preparation of squeezed states of light. The mode-matching and fringe locking technique should be employed to improve the stability of the optical parametric oscillator cavity. How the mode-matching efficiency influence the squeezing degree of the squeezed light and the locking accuracy of the fringe locking technique were analyzed theoretically. Then the fringe locking technique was employed to stabilize the optical parametric oscillator cavity after the mode-matching between the laser mode and the fundamental mode of the cavity. The theoretical and experimental results show that a perfect mode-matching would improve the squeezing degree and the locking accuracy of the fringe locking technique, when the mode-matching is optimized, the length variance of the cavity is 7.35 nm and the locking time is no less than 2 h, which is sufficient for the detection of the squeezed states of light.