偏振模色散(PMD)已成为高速光通信系统的主要限制因素，为了研究它对光通信系统的影响，研制出了多种PMD模拟器代替实际光纤进行实验研究。文章介绍了3种一阶PMD模拟器的原理及其结构，并用固定分析法对其差分群时延(DGD)值进行了测量，对其性能进行了分析比较。实际操作中可根据实验目的来选择恰当的模拟器。

Polarization Mode Dispersion (PMD) has become the main limiting factors on the high-speed optical fiber communication system, and in order to research it’s effects on the optical fiber communication system, many kinds of PMD emulators have been developed to replace the real optical fiber for experiment researches. The principles and configurations of first-order three kinds of polarization-mode-dispersion emulators are introduced in this paper. Using the fixed analyzer method measures their differential group dispersion values. Their performances are analyzed and compared and the right PMD emulator will be selected according to the experiment purpose.