基于速率方程理论对低重复频率高功率脉冲抽运Er-Yb共掺光纤放大器(EYDFA)进行了理论研究。通过采用有限差分法对理论模型的求解，系统分析了在放大自发辐射(ASE)受限情况下，抽运脉冲峰值功率、抽运脉宽、信号时延对放大器性能的影响。结果表明，在将ASE控制在合理范围的情况下，抽运脉冲存在一个最佳的抽运脉冲宽度，信号脉冲相对抽运脉冲的时延对输出峰值功率和脉冲能量有非常重要的影响。而且对给定的增益介质，抽运脉冲峰值功率也并非越高越好，而是存在一个最佳值。该研究结果对高功率脉冲抽运Er-Yb共掺光纤放大器的实验研究具有指导意义。

Low-repetition rate high-power pulse-pumped Er-Yb codoped fiber amplifiers (EYDFAs) are theoretically investigated. By numerically solving the rate-equations of EYDFAs with finite difference method, in the case of limited amplified spontaneous emission (ASE), the impact of the peak-power and pulse-width of pump pulse and time-delay between signal and pump pulse on the performance of the amplifier are systematically analyzed. The results show that the pulse width of pump pulse and the time delay between the signal and pump pulses have significant impact on the performance of EYDFA. They can be optimized by controlling the power of the ASE in a reasonable range. For a given gain medium, a low peak power long pump pulse is generally better than a high peak power short pulse, and there is an optimum value. These results are of great importame in high-power pulse-pumped Er-Yb codoped fiber amplifies.