实用型双气室气体传感器系统

Design of Applied Two Gas Cells Sensor for Gas Detection

基于气体的近红外吸收机理,研究了一种双气室光纤气体传感器。通过光纤光栅和压电陶瓷对宽带光源LED进行波长调制,获得与气体吸收峰对应的窄带反射出射光,检测二次谐波,实现气体浓度的较高灵敏度测量。利用测量气室和参考气室的二次谐波的比值来消除吸收系数随环境的变化、光源光功率的波动和光路干扰对测量精度的影响。利用该系统对CH_4气体进行了实验研究,实验表明该系统的测量灵敏度可以达到1×10^(-5)。

Based on the near infrared absorption of gases, an optical fiber gas sensor with two gas cells was described. The LED was used as a light source and wavelength modulation was realized by modulating on fiber grating and piezoelectric ceramics （PZT） to abstain narrowband reflection output light, the high sensitivity detection of gases can be achieved from the second har- monic signal. The ratio of the two second-harmonic signals from the measurement gas cell and the reference cell can be used for e- liminating the interferences of the optical route to the high sensitivity detection, the change of absorb modulus with the environment and the fluctuate of the laser＇s power. The experiments of CH4 detection with the system were studied. Experiment proves the measurement sensitivity of the system is 1 × 10 ^-5 .