针对基于背向衍射图像的熊猫光纤定轴法需要建立标准图样库的难题,进行了熊猫光纤在不同方位角所产生的背向衍射图样相关性分析的实验研究.实验显示:快轴方向的背向衍射图样与慢轴方向的背向衍射图样之间具有差异性;在快轴或慢轴方向附近的背向衍射图样之间具有相似性;快轴或慢轴方向的背向衍射图样自身具有对称性.根据差异性、相似性和对称性这三个特性,建立了一种基于熊猫光纤背向衍射图样的图像互相关定轴方法,用于确定熊猫光纤快轴或慢轴这些特殊方位角.此方法不用建立标准图库就可以实现熊猫光纤特殊方位角的定轴.
Experiments on the correlation analysis of backward diffractive patterns in different azimuths to determine the polarization axes of PANDA fiber were made in order to solve the problem to built a standard library of diffractive patterns. The experiments show that there are three characteristics of the patterns: the diffraction patterns in the fast axis direction is different from that in the slow axis direction; the diffraction patterns near the fast or slow axis are similar, and the diffraction patterns in the fast axis or the slow axis direction are symmetric. Based on the three mentioned characteristics,a new method without standard library of diffractive pattern was put forward to determine the special azimuths of polarization axes of PANDA fiber with image cross correlation. It is not necessary to build a standard library for the diffractive images to determine the special azimuths of polarization axes of PANDA fiber.