C2H6作为温室气体之一, 对光化学污染的产生和臭氧层的破坏具有促进作用。C2H6在大气中的含量极低, 对传感器的探测精度具有较高要求。报道了一种使用中红外连续波长带间级联激光器(ICL)检测大气中C2H6浓度的传感器, 其测量精度可达到10-9量级。采用容积为220 mL、光程为54.6 m的多通池增加气体吸收光程,降低检测下限, 提高灵敏度。采用LabVIEW虚拟仪器平台编程产生激光器扫描、调制信号及其叠加, 通过数据采集卡(DAQ)输出到ICL驱动源。通过DAQ读取探测器输出信号, 由LabVIEW程序进行信号的锁相放大及二次谐波提取。实验结果表明：当系统采样时间为1.67 s时, 阿伦标准差为1.86×10-9, 且阿伦标准差在平均时间为775 s时达到最小值, 即系统达到最佳稳定度, 为0.026×10-9。将该系统放置于燃气站进行检测实验, 证明所研制的C2H6传感器具有实用价值。

As one of the greenhouse gases, ethane can promote the generation of photochemical pollution and destruction of ozone. Due to its extremely low concentration in the atmosphere, it requires a sensor with high accuracy for measurement. A continuous-wave interband cascade laser (ICL) based on mid-infrared sensor system with high-precision of 10-9 level is demonstrated for detection of ethane in atmospheric. A multi-pass gas cell with volume of 220 mL and an optical path of 54.6 m is used. The LabVIEW visual instrument platform is used to program the scan and modulation signal as well as their superposition. A date acquisition (DAQ) card is employed to output the signal of the ICL driver. The output signal from detector is acquired by the DAQ and programmed by LabVIEW for data processing such as lock-in amplifier and second-harmonic extraction. Experimental results show that an Allan deviation of 1.86×10-9 for ethane with an averaging time of 1.67 s is achieved, and it is as low as 0.026×10-9 at an averaging time of 775 s. Outdoor atmospheric ethane concentration measurement is carried out in a compressed natural gas station. The experimental result shows that this ethane sensor system has a great practical value in application.