A longer laser resonator length is benefit for laser linewidth, but harmful for single-frequency operation. 增加激光谐振腔腔长是获得窄带宽的有效方法，但是使实现单频工作困难。
The analysis shows that the measurement precision drops rapidly with length misadjustment and spot offset brought by cavity mirrors' tilt. 分析表明，腔镜微小倾斜产生的衍射损耗的变化可以忽略，但导致的腔长变化和衰荡光斑漂移，会限制测量的精度。
