在应用可调谐二极管激光吸收光谱(TDLAS)技术进行气体检测时，气体检测精度受系统各功能模块性能的影响，针对这个问题研究了系统中光电探测器的输出电流噪声谱密度和响应度两种特性。推导出了探测器输出电流表达式，得出了输出电流噪声谱密度特性与激光器相对强度噪声(RIN)有关的结论，并通过实验验证了TDLAS 系统中激光器RIN 的存在。通过仿真，研究了RIN 对探测器输出电流的影响，给出了不同条件时的电流噪声谱密度曲线。为避免环境温度的变化影响光电探测器响应度，采用一种实时校正方法，给出了其原理及校正公式。以氨气为检测对象，运用该方法对氨气浓度曲线进行校正。

The precision of gas detection is affected by each function module performance of the system, when tunable diode laser absorption spectroscopy (TDLAS) is applied in gas detection. So the output current noise spectral density and the responsivity characteristics of photo detector are studied. The paper deduces the expression of the output current of photo detector, and the conclusion that the current is related to laser relative intensity noise (RIN), which exits in TDLAS experimental system. Effect of RIN on the output current of photo detector is studied by simulation, and the curve of current noise spectral density on different conditions is given. To avoid the photo detector responsivity being affected by ambient temperature, a real- time correction method is designed with the given principle and formula. Taking ammonia gas as an example, the concentration curve is corrected by using the method.