基于光谱吸收型光纤瓦斯探测传感器的研究

摘要

为了改善瓦斯传感器的测量灵敏度和误差,根据光谱吸收原理和谐波检测技术,采用分布反馈式半导体激光器(DFB LD)为光源,光电二极管为探测元件,设计了以锁相放大器为核心的光纤瓦斯探测传感器系统.采用单光路传输和光源调制技术实现瓦斯气体的谐波检测.根据二次谐波和一次谐波比值与瓦斯浓度的关系,拟合出二者的线性关系曲线,在理论和实验上均证明了该传感器具有较高的探测灵敏度和重复性,测量误差较小,为其在矿井瓦斯浓度预警奠定了应用基础.%In order to improve the measurement sensitivity and error of the gas sensor,according to spectrum absorption and harmonic detection technology,the optical fiber methane.The detection sensor was designed with phase-locking amplifier serving as core element,using distributed feedback semiconductor laser(DFB LD) as source and photodiode as detecting element.The harmonic detection of methane gas was realized by single light beam transmission and sinusoidal modulation technology.In the light of the relationship between methane concentration and proportionality between fundamental harmonic and second harmonic,the linear curve was fit.The theory and experiment all verified that the sensor has high detection sensitivity,repeatability and low measurement error,laying foundation for its application in coal mine methane concentration alarm.