为了消除固定分析仪法测量偏振模色散系统中的噪声, 提高测量精度, 提出了一种基于经验模态分解自适应滤波法的偏振模色散测量方案。该滤波法将信号按照其频谱特征进行多层分解, 获得有限个频率从大到小的本征模态函数, 利用连续均方误差准则进行噪声滤除及信号重构, 有效地消除了噪声对测量结果的影响。实验对比了经验模态分解自适应滤波和维纳滤波2种滤波方案的测量结果, 并与商用偏振模色散测量仪的测量结果进行了比较。结果表明, 对不同种类、长度的光纤, 本方案的测量结果与参考值的误差最大为0.74%, 明显提高了测量结果的精度。

In order to improve measurement accuracy in the polarization mode dispersion (PMD) measurement system by the fixed analyzer method, the noise in the link should be eliminated. Here, a polarization mode dispersion measurement scheme based on empirical mode decomposition (EMD) adaptive filtering to mitigate noise is proposed. According to signal spectral characteristics, it is decomposed into a finite number of intrinsic mode functions (IMFs), which are arranged by frequency from large to small. The consecutive mean square error (CMSE) criterion is used for noise filtering and signal reconstruction, which effectively eliminates the noise impacting on the measurement results. The experiments compare results based on the EMD adaptive filtering method, Wiener filtering method and commercial instruments. The results show that this scheme is suitable for different types and lengths of fibers, and the maximum relative error between the measured result and the reference value is 0.74%. The measurement accuracy is improved obviously.