摘要
基于可调谐二极管激光吸收光谱的光纤气体传感器检测气体浓度,具有灵敏度高、选择性好、响应时间快等优点。目前报导的基于二次谐波的气体浓度检测系统,普遍采用一次、二次谐波幅值之比作为系统输出,消除光强波动的影响。研究中分析了二次谐波检测方案的特点与不足,提出利用一次谐波检测甲烷的浓度,以一次谐波峰峰值与平均值的比值作为系统输出,系统结构简单,并可抑制光源波长漂移和扫描步长等因素对系统检测精度的影响。实验结果表明甲烷的浓度与系统输出值之间具有很好的线性关系,其线性拟合系数为0.999,系统的分辨率和检测精度分别为20×10-6和100×10-6。
Optical fiber gas sensor based on tunable diode laser absorption spectroscopy （TDLAS） is used to measure gas concentration, which has the advantages of high-sensitivity, good-selectivity and fast-response time and etc. Currently reported second harmonic concentration detection system uses the ratio of first and second harmonic amplitudes as the system output to eliminate the influence of optical intensity fluctuations. This paper analyzes the characteristics and shortcomings of this method and proposes a new method, which uses first harmonic signal to measure methane concentration. The proposed first harmonic detection system uses the ratio of first harmonic peak-peak value and its average value as the system output, which has a simple structure and inhibits the influence of laser wavelength shift and scanning step length. Experiment results show that there is a good linear relationship between methane concentration and system output, the linear fitting coefficient is 0.999, and the resolution and detection precision are 20×10^-6 and 100×10^-6, respectively.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2010年第11期2597-2602,共6页
Chinese Journal of Scientific Instrument
关键词
光纤气体传感器
可调谐二极管激光吸收光谱
波长漂移
扫描步长
optical fiber gas sensor
tunable diode laser absorption spectroscopy （TDLAS）
wavelength shift
scanning step
