应用带完全匹配层边界条件的全矢量有限元方法,分析了高折射率椭圆芯布拉格光纤的偏振特性,详细讨论了光纤结构参量对模式双折射度以及群速度走离的影响,结果发现：高折射率椭圆芯布拉格光纤的模式双折射度可达10-2量级,比传统保偏光纤至少高出一个量级,并且表现出不同于传统保偏光纤的群速度走离特性;在保持较高双折射度的同时,通过合理的结构设计,可在一定的波长处灵活地获得较大的群速度走离或零走离特性,具有重要的潜在应用价值;最后,简要分析了低折射率区域的折射率变化对偏振特性的影响;研究结果有助于设计高性能的微结构保偏光纤。

The polarization properties of highindexellipticalcore Bragg fibers are investigated via fullvector finite element method with anisotropic perfectly matched layer boundary conditions. The dependence of mode birefringence and group velocity walkoff on the fiber structural parameters has been fully analyzed. It is shown that the birefringence of highindexellipticalcore Bragg fiber is on the magnitude order of 10-2, which is at least ten times that of the conventional polarizationmaintaining fiber, and the walkoff parameters exhibit quite unusual wavelength dependence different from that of conventional polarizationmaintaining fibers. These unusual properties allow the flexible combination of high birefringence and large or zero walkoff at suitable wavelengths,and it contains potential application value. And the influence on the polarization properties imposed by the refractiveindex variance in the lowindex region is also briefly discussed. The results is helpful for the design of microstructured polarization-maintaining fibers with high performance.