We present a method for calculating the optical axis contour in laser cavities using the geometric optics approximation. The deviation of the position of the optical axis in four-mirror nonplanar ring cavities is calculated for various cavity perturbations. Various types of laser cavities are considered and classified according to their symmetry. Deviations of the optical axis are determined in a nonplanar ring cavity that provides Kerr mode locking operation. A formula is given that relates the bend angle in four-mirror cavities to the angles of radiation incidence on the mirrors.

中文翻译：

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激光腔内光轴位置的计算方法

我们提出了一种使用几何光学近似计算激光腔中光轴轮廓的方法。针对不同的腔扰动计算了四镜非平面环形腔中光轴位置的偏差。各种类型的激光腔根据它们的对称性被考虑和分类。光轴的偏差在提供克尔锁模操作的非平面环形腔中确定。给出了一个公式，该公式将四镜腔中的弯曲角与反射镜上的辐射入射角相关联。