基于差分吸收法,研究了一种光纤瓦斯传感系统.采用双波长参考测量法,选取输出波长为1 551 nm的分布式反馈半导体激光器作为参考光源,输出波长为1 653 nm的激光器作为甲烷气体的吸收峰处光源,通过改变甲烷气体吸收峰处激光器的输出波长,使其扫描到甲烷气体的吸收峰,通过比较吸收峰处和没有吸收峰处的光功率,测得甲烷气体浓度的分辨率达到0.038%.实验结果表明该系统的分辨率高、稳定性好、抗干扰能力强,可用于对煤矿瓦斯气体的检测.

Optical fiber methane gas sensing system based on differential absorption was investigated. Two distributed feedback laser diodes were used in the system. The wavelength of the reference light source was 1551nm and the wavelength of the measurement light source was 1653nm, which was located around the absorption peak wavelength of methane. The methane absorption peak was detected by scanning the wavelength of the measurement light source, and then the concentration of methane was measured by comparing the output power at the absorption peak with that not at the absorption band. The system possesses the properties of high resolution, good stability and a measurement resolution of 0.038% is achieved for methane detection.