无源谐振腔的有效谐振频率(被测得谐振频率)偏移作为参考的基模谐振频率的效应是谐振腔中存在的高阶横模所引起的。由光探测器光接收孔径的有限性或表面的不均匀性而导致各阶横模的空间不正交性, 是引起谐振频率偏移效应的主要原因。对此作了详细研究, 并对计算结果进行了讨论, 总结出谐振频率偏移与谐振腔各参量的相互关系, 从而提出减小这种效应的有效措施。

The effect that the valid resonance frequency (the measured resonance frequency ) offsets fundamental resonance frequency which is used as reference, is attributed to the presence of higher-order transverse modes in the cavity. The effect,which is mainly due to the non-orthogonality of these modes that is caused by a limited aperture or an inhonogeneous surface of the detector, has been carefully studied. The results of calculation are discussed and the relationship between the resonance frequency offset and the parameters of the cavity is generalized. Methods to minimize the effect are suggested.