端面成像熊猫保偏光纤的偏振轴检测方法及精度分析

Research on the detection of polarization axis of Panda polarization maintaining fiber and the accuracy analysis

针对目前已有的横向观测偏振轴检测技术精度不高的问题,提出了一种端面成像保偏光纤(PMF)偏振轴高精度检测方法,采用基于轮廓特征的自适应阈值分割技术提高应力区识别的速度和鲁棒性,采用同心圆加权平均定位技术提高应力区的定位精度,并分析了定轴误差的影响因素。仿真和实验表明,本文的端面成像PMF偏振轴检测方法能够达到±0.1°的精度。

The detection and alignment of polarization axis is a key technique in the applications of polarization maintaining fiber（PMF）.Considering the fact that the detection accuracy of PMF′s polarization axis using the transverse observation method is not high,this paper proposes an accurate detection method based on image processing of PMF′s end surface.Firstly,this method speeds up the recognition of PMF＇s stress area and enhances the recognition robustness through the application of an auto-adaptive threshold segmentation based on three characteristics of the contour of the stress area.Then the method improves the location accuracy of the center of PMF＇s stress area by using an accurate location technology,which includes three steps that are extracting concentric circles corresponding to different gray values,fitting circles with interring method to exclude non edge points,and calculating the weighted mean of the centers of the fitting circles.Finally,we analyze the influence factors of polarization axis alignment and establish an error formula for polarization axis alignment.The experimental results show that the recognition algorithm in this paper costs less time and has higher robustness to different light environment conditions than the traditional method of template matching.Besides,both the simulation results and experiment results indicate that the detection algorithm in this paper can achieve the accuracy less than±0.1°.