为了能高灵敏度地检测CO2气体的体积分数, 基于红外光谱吸收原理, 设计了一种以9m长的空芯光子晶体光纤作为传感单元的CO2气体传感器。利用该传感器测量了不同体积分数的CO2在同一吸收波长下的吸收光谱图。结果表明, 气体的吸收光强和气体的体积分数之间呈线性变化, 与比尔-朗伯定律一致; 传感器的灵敏度可达4.389×10-5W。可通过加长光子晶体光纤的长度, 来增加气体吸收的有效距离, 使传感系统获得较高灵敏度。

In order to get high sensitivity detection of volume fraction of carbon dioxide gas, a carbon dioxide gas sensor based on the principle of infrared spectrum absorption was designed by using 9m hollow-core photonic crystal fiber as sensing unit. The absorption spectra of carbon dioxide gas with different volume fractions were measured under the same absorption wavelength. The analysis results show that the linear relationship between gas absorption intensity and volume fraction of gas is presented, in accordance with Beer-Lambert law. The detective sensitivity of the system is estimated to be 4.389×10-5W. It can make the system get higher sensitivity by lengthening the photonic crystal fiber and increasing the effective distance of gas absorption.