一种基于温控半导体激光波长扫描的光纤瓦斯测量系统

设计了一种基于温控半导体激光波长扫描的光纤煤矿瓦斯测量系统，通过改变中心波长1653 nm半导体分布式反馈( DFB)激光器的工作温度来扫描半导体DFB激光器的输出波长，在5 nm波长扫描范围内，存在明显的瓦斯气体吸收峰。半导体DFB激光器输出的光注入被测气体室，气体室的输出光携带有瓦斯气体浓度信息，用光电探测器将光信号转化为电信号，再由A/D采集卡采集到信号处理系统，通过对有吸收峰位置的光功率和无吸收峰位置的光功率进行比较，则可计算出瓦斯浓度。该传感系统采用80 mA恒流源驱动半导体DFB激光器，使其输出光强保持不变，其结构简单、灵敏度高。

Optical Fiber Methane Sensing Systems Employing Wavelength-Scanning Based Temperature Control Techniques

Fiber￣optic coal methane gas sensing measurement systems, which employ wavelength￣scanning based temperature control technologies,are designed and investigated for some experiments. By changing operating tempera￣ture of DFB laser with the center wavelength of 1 653 nm to scan its output wavelength,there are some absorption peaks of methane gas among the wavelength scanning ranges of 5 nm. After the DFB laser light is injected into the measured gas chamber, the optical output signals carrying gas concentration information, which are converted into electrical signals by photoelectric detector and data acquisition,are used to calculate the gas concentration by compa￣ring the absorption peak position to no absorption peak position of the optical power. Owing to the use of 80 mA constant current source for driving DFB semiconductor laser,this sensing system is with the advantages of stable output light intensity,simple structure and high sensitivity.