偏振模色散模拟器的特性

Theoretical study of polarization mode dispersion emulators

通过对微分群时延差 (DGD)统计特性和偏振模色散 (PMD)矢量自相关函数的数值模拟 ,分析比较了目前常用的三种PMD模拟器的性能 .结果表明 :在DGD分布方面 ,由DGD发生器构成的模拟器 ,一个DGD发生器就可与实际光纤PMD的统计特性相符合 ,而由保偏光纤和可旋转的连接器构成的模拟器则至少需要 15段 .在自相关函数方面 ,基于保偏光纤的模拟器取决于各段光纤的延时量 ,而基于DGD发生器的模拟器在中心频带外的自相关值很平稳 ,可视为常数 .

The performances of the three polarization mode dispersion (PMD) emulators commonly used today are analyzed and compared among them through numerical simulation of their differential group delay (DGD) statistical characteristics and PMD vector autocorrelation function. The results demonstrate that to produce DGD that can match theoretical distribution, one DGD generator is adequate, while at least 15 sections are necessary in the emulator built by polarization maintaining fibers and rotatable connectors. And the autocorrelation function of the emulator based on polarization maintaining fibers depends on DGD of every section, while that of the emulator based on DGD generators is smooth and can be regarded as constant outside the central frequency range.