增益平坦度是衡量光纤通信中喇曼光纤放大器的关键参数之一。文章从级联光纤实现喇曼增益谱平坦技术的分析理论入手,改进了实现喇曼增益谱平坦的约束条件,利用Matlab分析了光纤损耗对RFA增益谱平坦度的影响。结果表明:在喇曼光纤放大器系统中,C波段各个光之间不同的损耗系数是影响增益平坦度的关键因素,即信号光之间损耗系数的不同会引起喇曼光纤放大器的增益平坦度劣化,各个被放大信号光之间的损耗系数相差越大,则增益平坦度越差。 Gain flatness is one of the key parameters for measuring Raman fiber amplifiers in fiber-optic communications. The article starts with the analysis theory of Raman gain spectrum flattening technique for cascaded fiber, improves the flattening condition of Raman gain spectrum, and analyzes the influence of fiber loss on the flatness of RFA gain spectrum by using Matlab. The results show that in the Raman fiber amplifier system, different loss coefficients of C-band light are the key factors that affect the flatness of gain. The difference of loss coefficients between signal lights will cause the gain flatness of Raman fiber amplifier to deteriorate , The greater the difference between the loss coefficients of the respective amplified signal lights, the worse the gain flatness.