提出了一种基于双芯光子晶体光纤(PCF)的具有短长度和超高消光比的偏振分束器，利用全矢量有限元法(FEM)对双芯PCF的耦合特性和偏振分束器的性能进行了数值研究。研究结果表明：增大纤芯间椭圆孔椭圆率、适当提高掺杂折射率可显著降低双芯PCF的耦合长度；基于该双芯PCF设计的偏振分束器在1.55 μm 波长处，长度为0.58 mm时，可以实现x，y 偏振态的分离,消光比达到82.33 dB，消光比高于20 dB的带宽为70 nm，高于10 dB的带宽达到110 nm，覆盖了C+L波段。这为设计具有短长度、高消光比、宽带特性的PCF偏振分束器提供了一种新的结构。

A polarization splitter based on dual-core photonic crystal fiber (PCF) with short-length and ultra-high extinction ratio is proposed, and the coupling property of the dual-core photonic crystal fiber and the performance of the splitter are studied numerically based on full vector finite element method (FEM). It is found that the coupling length of the dual-core PCF can be reduced obviously by enlarging the ellipticity of the hole between the two cores and adjusting the doped index properly, a polarization splitter based on the proposed dual-core PCF with a length of 0.58 mm is achieved that can separate the x polarized light and y polarization lights and the extinction ratio of the splitter can reach 82.33 dB at the wavelength of 1.55 μm. Meanwhile, the bandwidth of extinction ratio more than 20 dB and 10 dB can be as wide as 70 nm and 110 nm, respectively, which covers the C+L wavelength bands. This proposed splitter provides a new structure for designing a splitter with short length, wide bandwidth and high extinction ratio.