为了实现全光纤型高灵敏度气体在线检测系统, 以空芯光子晶体光纤为传感气室, 利用CO2气体分子在1 572.48 nm附近吸收谱以及虚拟仪器LabVIEW平台搭建了双光路差分CO2气体近红外检测实验系统。实验中所用空芯光子晶体光纤长度为1.8 m, 通过对其两端同时充气, 提高了系统响应速度, 0.1 MPa下充气过程仅需100 s左右。以标准浓度CO2气体对该系统进行了标定, 并对浓度2%、5%、10%和100%的CO2气体进行了测量, 结果表明100 min内浓度检测相对误差不超过2%, 标准差最大3.32%。气体吸收光程为1.8 m, 系统检测灵敏度达到5.981 8×10-5 μW/ppm。

For the purpose of realizing the all-fiber gas detection system with high sensor sensitivity, using the Hollow Core-Photonic Crystal Fiber (HC-PCF) as gas cell, a dual-optical path differential near-infrared carbon dioxide detection experimental system based on virtual instruments LabVIEW and the absorption spectroscopy around wavelength 1 572.48 nm of carbon dioxide molecule was developed. The system response time was about 100 s by inflating the HC-PCF of 1.8 m long from two ends under the pressure of 0.1 MPa. The detection system was calibrated with carbon dioxide of standard concentration. Carbon dioxide with known concentration of 2%, 5%, 10% and 100% were tested respectively and the experimental results showed that the detection errors relative to standard concentration were no more than 2% and the maximum standard deviation of measured concentration were 3.32% in 100 minutes. In addition, the optical path of gas absorption reaches 1.8 m and the system detection sensitivity of 5.981 8×10-5 μW/ppm was achieved.