对掺铒光纤L-波段的增益谱特性进行了理论模拟与实验,确定了形成平坦增益谱的最佳粒子数反转条件(～40％);采用两段级连分配抽运放大光路,小信号增益>36dB,最低噪声系数<4.4dB,在不加增益平坦滤波器的条件下,23±0.5dB的本征平坦增益带宽达到33.5nm(1569～1602.5nm)。 The gain spectrum characteristics of L-band of erbium-doped fiber were simulated theoretically and experimentally, and the best particle number inversion condition (~ 40%) for forming flat gain spectrum was determined. Two stages of cascaded pump amplifier were used to amplify the light path, Signal gain> 36dB, the minimum noise figure <4.4dB, without gain flatten filter conditions, 23 ± 0.5dB of the intrinsic flat gain bandwidth of 33.5nm (1569 ~ 1602.5nm).