在理论上和实验上对掺Yb双包层光纤放大器(YDCFA)的瞬态增益特性进行了研究建立了简化的瞬态增益基本模型,数值计算了低频光脉冲经过双包层光纤的放大波形,分析了瞬态增益饱和和恢复特性在实验中对种子源放大的YDCFA的脉冲特性进行了分析,证实了其瞬态增益的低频响应特性 The transient gain characteristics of Yb-doped double-clad fiber amplifier (YDCFA) are theoretically and experimentally studied. A simplified transient gain model is established. The amplified waveform of the low-frequency optical pulse passing through the double-clad fiber is numerically calculated. The pulse characteristics of YDCFA amplified by seed source are analyzed in the experiment, and the transient response of the transient gain is confirmed