设计并研究了一种在较宽波段范围内具有高双折射率和单模极化保偏的PCF（光子晶体光纤）。采用FVFEM（全矢量有限元法）和APML（各向异性完美匹配层）为边界条件研究该PCF基模的双折射率和极化保偏特性。仿真结果表明，通过将平行于横轴的椭圆形空气孔旋转45°，再将平行于纵轴的椭圆形空气孔向另一方向旋转45°，所得PCF的双折射率高达4.65×10-2，且具有良好的单模特性，可用于各类光学设备。

In this paper, we propose and study a novel structure of Photonic Crystal Fiber (PCF) with improved birefringence and single-mode propagation condition in a broad range of wavelength. The birefringence of the fundamental mode and single mode property in such a PCF is numerically investigated by Full Vector Finite Element Method (FVFEM) and Anisotropic Perfectly Matched Layers (APML).The simulation results show that by filling the silica into one line elliptical air holes parallel to x axis and rotated by an angle of θ=45°, and introducing one line elliptical air holes parallel to y axis without any material and rotated by an angle of θ=45° to other direction, the birefringence can be 4.65×10-2 with good single mode condition. Obviously, the proposed PCF has the potential application in optical instruments and devices.