为了研究适用于描述正弦波扫描波长调制光谱中相对波长响应的方法, 提高正弦波扫描测量气体浓度的准确性, 对现有的描述激光器相对波长响应的方法进行了讨论。首先, 分析现有的几种描述激光器波长响应的方法是否适用于正弦波扫描。然后, 比较由不同方法模拟的相对波长响应和实测的激光器波长响应残差, 残差越小说明激光器波长响应越准确。最后, 用确定的准确快捷的方法测量二氧化碳气体浓度。实验结果表明, 由电流扫描波长响应（CSWR）直接确定相对波长响应（RWR）的方法描述激光器的波长响应更准确。将得到的相对波长响应与通过标准具实测的结果进行比较, 二者残差的标准偏差小于5×10-3 cm-1。利用该方法结合多光程池技术和免定标波长调制技术, 能够准确测量二氧化碳的气体浓度。

In order to identify a method suitable for describing the Relative Wavelength Response (RWR) in the sine wave scanning wavelength modulation spectrum, and to improve the accuracy of the sinusoidal scanning measurement of gas concentration, existing methods for describing the RWR of the laser are discussed. First, several existing methods for describing the wavelength response of a laser for sinusoidal scanning are analyzed. Then, the RWR simulated by the different methods and the residuals of the measured laser wavelength response are compared. The smaller the residual, the more accurate the wavelength response of the laser. Finally, the carbon dioxide gas concentration is measured in a precise and accurate manner. The experimental results show that the method of directly determining the RWR by the current scanning wavelength response describes the laser wavelength response more accurately. The RWR obtained is compared with the results measured by the etalon, and the standard deviation of the residuals is less than 5×10-3 cm-1. By combining this method with multichannel cell technology and calibration-free wavelength modulation technology, the accuracy of the method was verified by measuring the concentration of carbon dioxide gas.