从理论上分析了迈克耳孙干涉仪测量保偏光纤偏振耦合强度分布时交叉耦合点的产生机理，并阐述了基于马赫曾德尔结构的偏振分束干涉仪测量保偏光纤偏振耦合强度分布的原理，并对一小段保偏光纤跳线进行测量对比实验。实验表明：基于马赫曾德尔结构的偏振分束干涉仪能够有效地避免耦合点之间的交叉耦合现象，比传统的基于迈克耳孙干涉结构的测量系统有更好的信噪比和测量准确度，给出的测量值与标准值相差仅为0.04 dB，并能够以串音或者消光比的参数形式呈现给用户。

The principle to rise the cross-coupling point when measuring the polarization coupling intensity distribution of polarization-maintaining fiber based on Michelson interferometer and the principle to measure the polarization coupling intensity distribution of polarization-maintaining fiber based on Mach-Zehnder polarizing beam splitters interferometer are analyzed. Contrast experiment is put up to a small portion of polarization-maintaining fiber jumper. The experimental results indicate that the signal-to-noise and the precision of the measurement of Mach-Zehnder are better than that of Michelson and Mach-Zehnder polarizing beam splitters interferometer can avoid the emergence of cross-coupling points. The error of measurement from Mach-Zehnder polarizing beam splitters interferometer is only 0.04 dB. The measuring results can be shown to user by crosstalk or extinction ratio.