提出一种可用于宽带偏振无关光定向耦合器的新型双芯光子晶体光纤(PCF),利用全矢量有限元方法分析了光纤结构参数对其光学特性的影响,得到了一组优化的双芯PCF结构参数,满足易于制作、易于接续和接续损耗低等应用要求,在此基础上对光纤结构进行了改进,进一步降低了制作难度,基于该光纤可以设计出在1.26～1.625μm范围内分光比误差小于1%、两偏振态分光比误差小于0.2%的50:50耦合器,并在现有实验条件下,试制了近似结构的双芯PCF。 A novel dual-core photonic crystal fiber (PCF), which can be used in wideband polarization-independent optical directional couplers, is proposed. The effect of fiber structure parameters on its optical properties is analyzed by full vector finite element method. An optimized double-core PCF Structural parameters to meet the requirements of easy to make, easy to connect and low loss of continued connection, on the basis of the optical fiber structure has been improved to further reduce the production difficulty, based on the optical fiber can be designed within the range of 1.26 ~ 1.625μm spectral ratio error Less than 1%, 50:50 coupler with error of less than 0.2% in two polarization states. The double-core PCF with similar structure was fabricated under the existing experimental conditions.