建立了计算轻微非共面腔输出光椭圆度的数学模型，分析了R. H. Moore专利中的理论计算错误，计算分析了输出片的应力作用对输出光椭圆度的影响，发现：输出镜片的应力作用对环形激光器顺时针方向和逆时针方向输出光椭圆度的非对称有影响。通过实验验证了理论计算的正确性。得出R. H. Moore, S. W. Hammons等人在专利中提出的调腔方法存在错误，它不能有效地消除环形激光器中由腔体轻微异面所引起的磁效应。

A mathematic model for calculating the ellipticity of the output beams in slightly noncoplanar resonators is given. By analyzing the error in the patent registed by R. H. Moore and taking the stress effect of the output mirror into account, the ellipticity of the output beams was analyzed. And it is found that the stress effect of the output mirror has the unsymmetrical influence on the clockwise and counterclockwise ellipticities of output beams. Moreover, the validity of the theoretical analysis is vertified by the experiment. Based on these results, the method proposed by R. H. Moore, S. W. Hammons et al.for aligning the light path can not reduce the magnetic effect by controlling the distortion angle of square ring resonators effectively.