400 Gbit/s单模光纤已经成为提高光纤传输系统容量的光纤研究热点。文章在介绍了单信道传输速率为400 Gbit/s的光纤传输系统的主要传输性能后，综述了400 Gbit/s传输系统使用的低损耗大有效面积单模光纤和低损耗大有效面积单模光纤的设计、性能及其在系统中的应用研究。通过系统传输实验、网络现场传输实验和对系统设备成本的研究表明，低损耗大有效面积单模光纤和超低损耗大有效面积单模光纤是构建“超高速率、超长距离和超大容量”传输系统的最佳光纤。

400-Gbit/s transmission in single-mode fiber is a hot research topic in fiber transmission system with higher channel capacity. After evaluating the performances of optical fiber transmission systems at 400-Gbit/s per channel, the paper reviews the designs, properties and applications of Low-Loss-Large Effective Area Fibers (LL-LEAF) and Ultra-Low-Loss-Large Effective Area Fibers (ULL-LEAF) in 400-Gbit/s transmission systems. After system transmission tests, network field transmission tests and system equipments cost comparison, LL-LEAFs and ULL-LEAFs are regarded as the optimal optical fibers in “ultra-high speed, ultra-long distance, ultra-large capacity” transmission systems.