针对光纤通信和传感系统中高双折射的应用需求，文章提出了一种新型光子晶体光纤，其包层由圆形空气孔按六角晶格结构排列而成，将最内层设计为4个椭圆空气孔和两个小圆空气孔。采用全矢量有限元法，通过改变内包层椭圆空气孔的椭圆率和圆形空气孔的大小，对该光纤的有效折射率、双折射系数、非线性系数和色散特性进行了仿真研究，仿真结果表明，当椭圆率为0.5，小圆孔直径为0.8 μm时，在波长为1 550 nm处可得到4.22×10-2的高双折射系数、109.65 km-1·W-1的高非线性系数和低至-14 ps/(nm·km)的色散值。文章提出的光子晶体光纤具有高双折射及高非线性的性质，可应用于光开关等领域，为光纤通信和光纤传感等方面的研究提供了理论基础。

To meet the application requirements of high birefringence in optical fiber communication and sensing system, a new Photonic Crystal Fiber （PCF） is proposed in this paper.The designed structure is hexagonal, which is arranged by circular air holes. The inner cladding is designed as four elliptical air holes and two small round air holes. By applying fullvector finiteelement method and changing the ellipticity and the size of small round air holes, we investigate the effective refractive index, high birefringence, nonlinear coefficient and dispersion characteristic of the fiber. The simulation results show that when the ellipticity is 0.5 and the diameter of small round hole is 0.8 μm, a high birefringence of 4.22×10-2，a high nonlinear coefficient of 109.65 km-1·W-1 and a dispersion value as low as -14 ps/(nm·km) can be obtained at 1 550 nm. The PCF proposed in this paper has high birefringence and high nonlinearity, which can be applied in the optical switch field and provide the theoretical basis for the research of optical communication and optical fiber sensing.