保偏光纤偏振耦合系统的动态色散补偿

在白光保偏光纤(PMF)偏振耦合系统中,光纤双折射色散会引起干涉条纹包络随着光纤长度展宽,从而导致空间分辨率降低,光纤测量范围变小。为了减小双折射色散的影响,提出一种基于频域变换的色散相位补偿方法,通过干涉主极大包络与耦合点包络的宽度比求得相位补偿因子,并与非线性色散相位谱相乘,通过傅里叶逆变换得到色散补偿信号。实验分别对400m和1000m PMF进行了测试,得到光纤双折射色散系数为0.0116×10-9 ps/(nm.km),将测试系统对PMF 1000m处耦合点的空间分辨率由62.85cm提高到6.03cm,实现了对长距离PMF偏振耦合系统的动态色散补偿。

Dynamic Dispersion Compensation for the Polarization Coupling Measurement System of Polarization Maintaining Fiber

In the polarization coupling measurement system using white light interferometry (WLI), birefringent dispersion would broaden the envelope of the interference pattern along the polarization maintaining fiber (PMF), which leads to a noticeable decline of the spatial resolution and the available measurement ranges of the system. To reduce the influence of birefringent dispersion, a new method is proposed for compensating the dispersion phase in frequency domain. By multiplying the dispersed spectral phase and the compensating phase, which is extracted by dividing the width of the principal maximum, we can obtain the non-dispersed signals with inverse Fourier transform. In the experiment, 400 m and 1000 m long fiber was tested respectively, and the birefringent dispersion coefficient of the fiber was obtained as 0.0116×10-9 ps/(nm·km). The spatial resolution of the coupling point at 1000 m PMF was improved from 62.85 cm to 6.03 cm. This makes the fast and real-time compensation of any dispersion in long distance fiber be possible.