基于气体的差分吸收检测原理和超窄带半导体激光器的光谱扫描技术, 设计了一种高精度分布式二氧化碳气体检测网络。 系统采用超窄带可调谐半导体激光器作为光源, 设计了新型气室结构, 通过方波信号对光源光谱进行调制, 消除了其他气体成分和灰尘颗粒的干扰, 并结合空分复用技术, 实现了二氧化碳的实时分布式检测。 利用超窄带光谱扫描技术测得了不同压强下二氧化碳分子在1 572.66 nm附近的弱吸收谱线并进行了分析。 实验结果表明系统浓度最低检测限为0.005%, 测量最大相对误差小于3%; 逐次充入一定体积二氧化碳气体, 动态响应时间小于8 s。

Based on the basic principle of differential absorption detection and the spectrum scanning technology of ultra-narrow-bandwidth (UNB) laser, a kind of distributed carbon dioxide detection system with high precision was designed. An UNB laser was utilized as light source and a novel structure gas cell was also used in this system. By using the wavelength modulation technique and space division multiple access technique, the interference of other gas and dust was eliminated and the distributed detection of carbon dioxide was achieved. With the spectrum scanning technology of UNB laser, spectra of carbon dioxide near the region of 1 572.66 μm at different pressures were obtained which were also analyzed. Finally the experiments indicated that the minimum detectable carbon dioxide is 0.005% and the measurement relative error is less then 3%. The system dynamic response time is less than 8 s by filling a volume of carbon dioxide gas into the gas cell gradually.