相关光谱法在光纤气体传感中的应用

本文提出了一种新的基于相关光谱法的光纤气体检测方案，在对传统相关光谱检测理论进行详细分析的基础上，提出了一种新的实现方案。这种方法继承了传统相关光谱法在信号检测的时候所具有的高选择性的优点，在调制方法上有创新，使得利用宽带光源（LED）在检测甲烷和乙炔等在近红外具有梳状吸收峰的气体时变得简单易行。本文对该系统进行了详尽的理论分析，在合理选择器材的基础上实际构建和调试了一个基于光谱检测的光纤甲烷气体检测系统。文中给出了存在干扰气体情况下检测结果。实践中干扰气体引起的信号变化相当于甲烷信号变化的7．4％，已经达到国际上相关光谱检测现有的最佳值。

Application of Correlation Spectroscopy Method to Fiber Gas Sensor

In this paper, we employ correlation spectroscopy method to detect gases and gas mixtures which have multi line absorption in near infrared. The theories of correlation spectroscopy are discussed and a new modulation measure is proposed, which inherits the excellence of the correlation spectroscopy and makes the modulation easy. Then we compare this method with the traditional correlation spectroscopy method. Experimental results for the selective detection of methane by this method are also presented. The change in signal from interference gas is only equal to 7 4% of that from methane absorption. It has been proven that the proposed method is practicable for both theory and experiment. This method can reach a high accuracy for mixed gas detection.