非通视方位传递系统中保偏光纤分析

根据非通视方位传递系统对保偏光纤双折射的设计要求，重点分析了不同类型保偏光纤参数对双折射的影响。首先，从光纤应力应变、变分原理和应力光弹效应出发，推导建立保偏光纤应力光学耦合关系；然后，借助有限元分析软件研究了不同因素对保偏光纤双折射值的影响，并对两种保偏光纤（熊猫型保偏光纤和领结型保偏光纤）进行了对比分析。结果表明:在纤芯中心附近，减小纤芯与应力区的距离、增大应力区半径大小、固定纤芯尺寸时增大包层半径、提高保偏光纤参考温度等措施都能明显提高双折射值。同等条件下领结型保偏光纤产生的双折射值更大。研究成果能够为非通视方位传递系统中保偏光纤的设计选型提供一定的参考。

Analysis of polarization-maintaining fibers in non-line-of-sight azimuth transmission system

According to the design requirements of the birefringence of polarization-maintaining fiber in the non-line-of-sight azimuth transmission system, the influence of different types of polarization-maintaining fiber parameters on the birefringence is emphatically analyzed. Firstly, the stress-optical coupling relationship of polarization-maintaining fiber was deduced based on the stress-strain, variational principle and the stress-photoelastic effect. Then, the influence of different factors on the birefringence of polarization-maintaining fiber was investigated by means of finite element analysis software, and two kinds of polarization-maintaining fiber (Panda polarization-maintaining fiber and Bow-tie polarization-maintaining fiber) were compared and analyzed. The results show that the higher birefringence value near the center of the core can be obtained by a variety of methods, such as reducing the distance between the core and the stress zone, increasing cladding radius when fixing core size, or increasing the reference temperature of the polarization-maintaining fiber. Simultaneously, the birefringence of the bow-tie polarization-maintaining fiber is larger in the same conditions. The research results can provide some reference for the design and selection of polarization-maintaining fiber in the non-line-of-sight azimuth transmission system.