从受激布里渊散射(SBS)耦合波理论出发，根据双包层光纤放大器中的受激布里渊散射阈值模型，理论仿真了信号带宽、纤芯直径、放大器增益对SBS阈值的影响，并从实验上研究了单频百纳秒脉冲信号在掺镱双包层光纤放大器中的受激布里渊散射现象。实验中输入脉冲信号重复频率1 Hz,脉宽200 ns，对不同的输入脉冲信号放大，前向放大脉冲在脉冲能量660 nJ、峰值功率3.3 W时出现畸变，产生后向SBS窄脉冲，达到了SBS阈值，实验计算的SBS阈值与理论分析结果基本一致。

Based on the wave coupling theory and the evolution model of the critical pump power (or Brillouin threshold) for stimulated Brillouin scattering(SBS) in doubleclad fiber amplifiers, the influence of signal bandwidth, fibercore diameter and amplifier gain on SBS threshold is simulated theoretically. And experimental measurements of SBS are presented in ytterbiumdoped doubleclad fiber amplifiers with singlefrequency hundred nanosecond pulse amplification. Under different input signal pulses, the forward amplified pulse distortion is observed when the pulse energy is up to 660 nJ and the peak power is up to 3.3 W in the pulse amplification with pulse duration of 200 ns and repetition rate of 1 Hz. And the backward SBS narrow pulse appears. The pulse peak power equals to SBS threshold. Good agreement is shown between the modeled and experimental data.