设计了一种新型近椭圆内包层(NEIC)结构的高双折射偏振保持光子晶体光纤(PCF),并利用带有各向异性完全匹配层吸收边界条件的全矢量有限元法(FEM)对这种光纤的特性参数进行了数值分析.结果表明这种结构的光子晶体光纤在1.55μm的双折射系数高达2.0×10-3,在长轴和短轴方向上的模场直径分别为9.2μm和2.4μm.同时当短轴方向最内层空气孔的孔径在1.30—1.18μm范围内变化时(孔径变化范围~10%),其双折射系数的劣化小于1.2×10-5,表明这种结构的偏振保持光子晶体光纤具有优异的偏振稳定性. A novel birefringence polarization maintaining photonic crystal fiber (PCF) with a near-elliptical inner cladding (NEIC) structure was designed and a full-vector finite element method (FEM) with an anisotropic perfectly matched layer absorbing boundary condition The results show that the birefringence coefficient of the photonic crystal fiber with this structure is as high as 2.0 × 10-3 at 1.55μm and the mode field diameters at the long axis and the short axis are 9.2μm and 2.4μm, and the birefringence coefficient was less than 1.2 × 10-5 when the pore diameter of the innermost pores in the short axis ranged from 1.30 to 1.18μm (range of pore diameter variation ~ 10%), indicating that this structure The polarization-maintaining photonic crystal fiber has excellent polarization stability.