基于小波阈值去噪的偏振模色散测量

Polarization Mode Dispersion Measurement Based on Wavelet Threshold Denoising

针对固定分析仪法在测量光纤偏振模色散时会引入误差、降低测量精度这一问题,提出了一种基于小波阈值的去噪方案,以提升固定分析仪法的测量精度。给出了算法的具体流程,并详细讨论了小波阈值、阈值函数、基函数以及分解层数的选取原则及方案。搭建了实验平台并进行测定,将测定结果与常用的傅里叶变换法及商用的偏振模色散测量仪的测量结果进行对比。实验结果表明,所提出的小波阈值去噪方案能够有效地降低噪声对测量结果的影响,且对于不同类型、不同长度的测试光纤样本均适用。以商用仪器的测量结果为参考,本方案测量结果的最大误差为2.27%,该数据表明本方案显著提升了固定分析仪法测量偏振模色散的精度。

The fixed analyzer method commonly used for measuring the polarization mode dispersion of optical fibers can introduce errors and reduce measurement accuracy, and thus a novel scheme based on wavelet threshold denoising is proposed to further improve the measurement accuracy. The specific workflow of the scheme is presented and the selection principle and scheme of wavelet threshold, threshold function, mother wavelet and wavelet decomposition layer number are discussed in detail. An experimental platform is built and the measurement is conducted. The measurement results are compared with those by the commonly used Fourier transform method and commercial polarization mode dispersion measurement instruments. The experimental results show that the proposed wavelet threshold denoising scheme can be used to effectively reduce the impact of noises on the measurement results and is also suitable for different types and lengths of test fiber samples. If the measurement results by commercial instruments are taken as the reference standard, the maximum error by the proposed scheme is 2.27%, which indicates the polarization mode dispersion measurement accuracy by the fixed analyzer method is significantly enhanced.