空芯光子晶体带隙光纤用于甲烷检测的研究

基于甲烷的光谱吸收理论,设计了一套利用空芯光子晶体带隙光纤(HC-PBGF)做传感气室的全光纤甲烷检测系统。根据HITRAN2012数据库和HAWKS软件确定甲烷的检测波长;利用气泵在HC-PBGF两端形成压力差来加快甲烷气体的扩散,利用反射镜延长光程至2倍;通过实验得到190s后气体扩散完成,0.5h内系统示值波动为0.012%,平均重复率为99.63%。最后配制0~2.5%浓度的甲烷气体进行浓度检测,得出甲烷浓度与相对吸收强度呈线性关系,线性度为99.92%。该系统成功实现了将HC-PBGF的空芯结构用于甲烷的吸收检测,加快了系统的响应速度,实现了仪器的小型化,使在线检测更加方便。

Research on the Detection of Methane Using Hollow Photonic Band Gap Fiber

All-fiber methane detection system based on the spectrum absorption properties of methane using a hollow-core photonic bandgap fiber (HC-PBGF) as special gas cell was demonstrated. The detection wavelength of methane was chosen on the basis of HITRAN2012 and HAWKS; In order to accelerate methane gas diffusion, pressure difference between inlet of HC-PBGF and outlet of HC-PBGF was formed with air pump. The optical path can be extended twice by using mirrors. The results indicated that the time is 190 seconds of the gas diffusion, system value fluctuation is 0.012% in half-hour and average repetition rate is 99.63%. Finally, making up different concentration methane gases, the results indicated that methane concentration has a good linear relationship with relative strength of absorption and the linearity is 99.92%. The detection system is response speed and portable on account of the hollow-core of HC-PBGF to detect methane and make online detection more convenient.