建立了基于自相位调制效应的掺Yb光纤激光器输出光谱特性的解析模型，实验测量分析了输出光谱的形态，输出光谱随功率升高的变化趋势以及低功率下的输出光谱特性。实验结果表明，理论模型与实验结果吻合地较好，并且能够较为准确地得到输出光谱宽度随功率的变化规律以及低功率下输出光谱的特性。

Based on self-phase modulation, an analytical model of Yb-doped fiber laser describing its output spectral characteristics has been developed. The output spectral shape, the variation trend of output spectrum along with the increased power, and its characteristics in low-power have been analyzed by experimental measurement. As the experimental results show, this analytical model agrees well with the experimental results, and through this model, the variation of the output spectral line width with the variational output power and the spectral characteristics in low power can be accurately obtained.