设计了一种高双折射低有效模场面积的光子晶体光纤(PCF)。利用有限元法依次研究了三层椭圆孔光子晶体光纤在纤芯中引入矩形排列的四个小椭圆孔，及其基础上再引入一个中心椭圆缺陷孔的五个小椭圆孔情况下的双折射和有效模场面积。研究表明：纤芯区域矩形排列的小椭圆孔主导了光子晶体光纤的双折射，中心椭圆缺陷空气孔中填充高折射率的材料可以获得更高的双折射和更低的有效模场面积，且波长1.55μm处光纤双折射达到了5.49×10-2，x与y偏振有效模场面积分别低至3.05μm2、2.42μm2。

A kind of highly birefringent photonic crystal fiber (PCF) with low effective mode area is proposed. The birefringence and effective mode area of photonic crystal fiber with a rectangular array of four elliptical holes, and five small elliptical holes with a central defected elliptical air hole in the core region were investigated respectively by using the full vectorial finite element method with anisotropic perfectly matched layers. It is shown that the birefringence property of PCF is mainly dominated by the rectangular array of four elliptical holes in the fiber core, and high refractive index materials are introduced into the central defected elliptical air hole for higher birefringence and lower effective mode area. The proposed PCF achieves high birefringence up to 5.49×10-2, low mode areas of 3.05μm2 and 2.42μm2 for x and y polarizations at 1.55μm.