针对模分复用系统中模式串扰问题，提出一种具有大模式差分群时延的微结构少模光纤，利用基于全矢量有限元分析法的Comsol计算其模场分布和有效折射率，同时分析光纤的模式差分群时延。仿真结果表明：该光纤在1.55 μm波长处，LP11、LP21、LP02与LP01的模式差分群时延分别为8.45、19.28和23.25 ps/m，与传统的少模光纤相比，该少模光纤具有良好的大模式差分群时延特性，能有效解决模间串扰问题，在模分复用系统中有着重要的应用。

In order to solve the mode crosstalk in the mode division multiplexing system, this paper proposes a kind of micro-structured few-mode fiber with high Mode Differential Group Delay (MDGD). The mode field distribution and the effective index are studied by using the Comsol software based on full-vector finite element method, and the MDGD is also analyzed. Simulation results show that the MDGD of LP11, LP21, LP02 versus LP01 are 8.45, 19.28, 23.25 ps/m, compared with the traditional few-mode fiber. It is also shown that the designed few-mode fiber has excellent high MDGD characteristics, which can solve the mode crosstalk problem efficiently, which may have important application in the mode division multiplexing system.