激光以其单色性好、能量集中等优点在测距、传感等领域获得了极为广泛的应用，而线宽是衡量激光单色性的重要指标，因此对窄线宽激光线宽测量的研究具有非常重要的意义。文章较为系统地介绍了几种基于相干光的拍频信号测量窄线宽激光线宽的方法，并对其进行了实验研究和对比分析。结果表明，采用带法拉第旋镜的迈克尔逊干涉仪结构是一种非常理想的窄激光线宽测量方法。

Lasers are widely applied in such areas as ranging and sensing for good monochromaticity and energy concentration and linewidth is an important index for measuring laser monochromaticity. Therefore, it is of great significance to investigate the methods for measuring narrow linewidth. This paper systematically introduces several heterodynebased methods for linewidth measurement and conducts the relevant experiments and comparative analysis. The results show that Michelson interferometer with Faraday rotator mirror is an ideal method for measuring narrow laser linewidth.