In this paper, a theoretical investigation of the influence of laser linewidth on the tunable diode laser absorption spectroscopy system is presented. The theoretical analysis and formula discussion of laser line shape are carried out by frequency noise spectrum density. Taking Lorentz line shape of laser line width as an example, the interaction principle of laser line width and gas absorption spectral line is analyzed. The relation curve of laser linewidth and maximum amplitude is simulated by MATLAB platform with self-defined simulation parameters. These results can provide theoretical basis for guiding the selection of laser and gas absorption spectral line and improving the detection accuracy of gas concentration.

在本文中，对激光线宽对可调二极管激光吸收光谱系统的影响进行了理论研究。通过频率噪声频谱密度进行了激光线形的理论分析和公式讨论。以激光线宽的洛伦兹线形为例，分析了激光线宽与气体吸收光谱线的相互作用原理。利用自定义的仿真参数，通过MATLAB平台仿真了激光线宽与最大振幅的关系曲线。这些结果可为指导激光和气体吸收谱线的选择和提高气体浓度的检测精度提供理论依据。