光纤甲烷气体传感器的研究

基于甲烷气体近红外吸收的机理，研究了一种高灵敏度易于实现的光纤甲烷气体传感器。分析了半导体激光器的调制特性和谐波检测的基本原理，建立了传感器的数学模型。系统采用分布反馈式半导体激光器做光源，气室采用小型渐变折射率透镜构成的气室，加入参考光路和参考气室，使光源输出的中心波长锁定在气体的吸收峰上，通过光源调制实现气体浓度的谐波检测，给出了甲烷气体测量的实验结果。

Research on Fiber Methane Gas Sensor

An easy-realizable fiber methane gas sensor with high sensitivity is demonstrated based on the near infrared spectral absorption of methane.The modulating characteristic of diode laser and the principle of harmonic detection are analysed.The mathematical model of sensor is built up.Distribute feed back laser diode is used as a light source.The gas cell used is made up with grin lens.The referenced optical path and referenced gas cell are appended so that the center wavelength of the diode laser is locked in the absorption peak of methane.Gas concentration harmonic detection is achieved by light source modulation.The experiment result of the methane detection system is shown.