提出了一种新的光纤拉曼放大器设计方法：在同一种光纤内运用不同波长的泵浦光源达到前增益后补偿的目的，最终实现在放大器输出端信号光增益谱平坦化。通过对拉曼增益谱前后沿做线性化处理，化简稳态SRS耦合波方程的解析解，最终在输出端得到了一个固定的功率输出值。模拟结果表明：所设计的放大器具有增益平坦度好、增益高的优点，且设计方法简单。该方案为增益平坦化的拉曼光纤放大器设计提供了一种新的思路。

We proposed a novel method for designing Raman fiber amplifier (RFA) which could achieve output signal gain spectra flattening by using pump lights with different wavelengths in the same fiber. We simplified the analytical solution of steady-state stimulated Raman scattering (SRS) equation by employing the linear model of leading and trailing edge of gain spectra, and obtained a constant output signal power at the output port finally. Simulation results de-monstrate that the designed RFA has advantages of flattened gain spectra, high gain as well as simple configuration. It provides a new way for the designing of gain-flattened RFA.