提出一种基于非准直平凹回馈腔的单频激光多重回馈光线追迹模型, 采用该模型阐明了单频激光多重回馈效应的产生机理, 分析了多重回馈高分辨率条纹的特性, 明确了影响多重回馈条纹形状的主要因素, 包括回馈镜的倾角、曲率半径、反射率以及回馈外腔长等, 获得了回馈镜在不同倾角时的有效回馈阶次及其耦合系数。光线追迹分析与实验结果表明: 当回馈镜倾斜角为1.7′时, 多重回馈效应会产生调制幅度均匀、没有大包络的高分辨率回馈条纹, 每个条纹的分辨率可达λ/50。

A ray tracing model of multiple optical feedback with asymmetric plane-concave cavity was presented. With this model, the generation mechanism of high-resolution fringes in single frequency laser multiple feedback was elaborated. Also, the affecting factors of fringe-shape were analyzed, including tilted angle, curvature, reflectivity of feedback mirror and length of external cavity. In addition, the effective feedback order and coupling efficiency of feedback beams with different tilted angles were obtained. Theory analysis and experimental results show that the high-resolution feedback fringes without envelopment can be obtained when the tilted angle is 1.7′. In particular, the resolution of feedback fringes can be λ/50, which is very important to explore high-precision displacement measurement system.