针对六边形晶格微结构光纤，采用有限差分波束传播法对多孔光纤的模式双折射特性进行数值模拟，分析了横截面结构参数的变化对模式双折射的影响。得到了两组合适的光纤结构参数，其偏振拍长可以在较宽的波长范围内基本保持稳定，具有较好的消色差特性：一种结构的偏振拍长在1310 nm波长附近的工作带宽可达200 nm；另一种结构的偏振拍长在1550 nm波长附近的工作带宽可达260 nm。这两种结构的光纤均适合制作宽带稳定的消色差波片。

In view of the hexagonal lattice micro-structure optical fiber, the modal birefringence characteristics of holey fiber are simulated by the finite difference beam propagation method. The influence of the different cross-section structural parameters on modal birefringence is analyzed. Two groups of appropriate structural parameters are obtained. The polarization beat lengths of these structures remain stable in a wide wavelength range，and thus better achromatic characteristics can be got. The working bandwidths of these structures reach 200 nm near the 1310 nm communication window and 260 nm near the 1550 nm communication window, respectively. The fibers are suitable for making wideband achromatic wave plates.