光纤喇曼放大器(FRA)系统中的偏振相关增益(PDG)降低光纤通信系统的传输性能,因此研究FRA系统中PDG的特性和如何降低FRA系统中的PDG成为FRA系统应用中的一项重要内容。论述了FRA的基本原理,总结了有关PDG的理论研究和实验研究,详细分析了降低FRA中偏振相关增益的几种方法,对FRA偏振相关增益的进一步研究方向进行了展望。 Polarization-dependent gain (PDG) in Fiber Raman Amplifier (FRA) systems reduces the transmission performance of optical fiber communication systems. Therefore, it is important to study the characteristics of PDG in FRA systems and how to reduce PDG in FRA systems as FRA system applications . The basic principles of FRA are discussed. Theoretical and experimental studies on PDG are summarized. Several methods to reduce the polarization-dependent gain in FRA are analyzed in detail. The further research directions of polarization-dependent gain of FRA are also discussed.