近红外波段CO高灵敏检测的稳定性研究

本文采用中心波长1566.64 nm的DFB激光器, 结合光程长度为56.7 m 的多次反射池, 对不同浓度的CO气体进行了长时间测量, 分析了系统的稳定性和线性度. 通过计算Allan方差, 预测了在积分时间为30 s时, 系统检测极限为0.25 ppmv, 基本上实现了在近红外波段CO的高灵敏检测. 关键词： 可调谐半导体激光吸收光谱 多次反射池 CO检测 Allan方差

Stability study on high sensitive CO monitoring in near-infrared

CO is an indicative gas of coal spontaneous combustion warning and mine production safety instruction, whose detection process generally requires fiber long-haul transmission. However, currently, the communication fiber windows are mainly in the near-infrared band, so it is very significance to realize highly sensitive CO detection at near-infrared band. Tunable diode laser absorption spectroscopy (TDLAS) technology has advantages of high sensitivity, high resolution, fast response ability and no-contact, which has been widely used in air pollution monitoring, industrial and agricultural production process control, and many other fields. Long-path multi-pass cell can effectively improve the TDLAS detection capabilities, at the same time, the whole system is more compact. In this paper, 1566.64 nm DFB laser and the novel multi-pass cell with an optical path 56.7 m are used to detect different CO concentrations in long-term, while the system stability and linearity are analyzed. In addition, the detection limit is 0.25 ppmv with 30 s integration time by calculating the Allan variance. It means that we have primarily achieved highly sensitive detection of CO in the near-infrared bands.
Keywords： tunable diode laser absorption spectroscopy (TDLAS) multi-pass cell CO detection allan variance