摘要 基于相关光谱和差分检测技术提出了一种新型的光纤气体传感系统，实现了对微量气体的高灵敏度、高准确度、实时在线检测.首先对该系统进行了详尽的理论分析，然后在合理选择实验器件的基础上搭建了一个光纤气体传感系统，测量乙炔气体的体积分数.该系统不仅消除了光强波动及待测气体中杂质气体的干扰，而且也避免了周围环境中噪声和杂散光的影响.实验结果表明，系统的分辨力可达0.5‰，测量灵敏度为6.62μV，最大绝对误差为0.15‰，相对误差为7.5%，稳定性为2.27%，重复性误差为0.817%.Abstract：Based on correlation spectroscopy and differential technology， a novel optical fiber gas sensing system was designed to realize high-sensitive， high-precision and real-time online detection of the trace gas. The theoretical basic of the system was analyzed in detail， and then appropriate devices for the sensing system were selected. Based on this， an optical fiber gas sensing system was constructed to measure the volume fraction of acetylene gas. The proposed system could not only eliminate the disturbances of light-intensity fluctuation and the contaminating gas in the measuring gas， but also avoid the influence of noise and ambient light in the surrounding environment. The experimental results showed that the system resolution could reach 0.5‰， the measurement sensitivity was 6.62μV， the maximum absolue error was 0.15‰， the relative error was 7.5%， the system stability was 2.27%， and the system repeatability error was 0.817%.
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