针对模式复用技术的特点，设计了一种用于模式复用的四模光纤。通过分析不同Δn(纤芯与包层的折射率差)值与少模光纤有效面积、有效折射率、微弯损耗以及色散之间的关系，确定合适的Δn值为0.96%。仿真分析了该少模光纤的模式特性，给出了光纤的主要参数，并与已有文献的相关参数进行了比较。结果表明: 所设计四种模式的光纤的有效面积达120μm2以上，损耗小于0.2dB/km，其他各项参数较好，是一种适合模式复用技术应用的少模光纤。

For the mode division multiplexing characteristic, a four-mode fiber suitable for mode division multiplexing was designed. By analyzing the relationship of different Δn (refractive index difference between core and cladding) with the effective area, effective refractive index, microbending loss and dispersion, the appropriate Δn value of 0.96% is determined. Simulations were performed on the pattern characteristics of the few-mode fiber and its main parameters were given. Comparisons with the parameters presented in existing literatures show that, the designed four-mode fibers obtain effective area of more than 120μm2 and loss of less than 0.2dB/km, which is suitable for mode division multiplexing.