波导式光学吸收腔在气体和液体浓度测量等领域有广泛的应用前景。空芯光纤作为光学吸收腔具有很多优点。空芯光纤的参数与传感系统的性能有直接的关系。提出了一种能同时考虑空芯光纤的损耗和系统信噪比的数学模型。从理论上分析了光纤的长度、内径、目标气体浓度以及输入光场能量分布等因素对传感系统信号输出强度和灵敏度的影响。给出的最优化参数为提高系统灵敏度和补偿系统误差提供了参考。

Optical waveguide has a promising application as absorption cell in concentration measurement for gases and liquids. Hollow fiber has many advantages when it is used as the absorption cell for spectroscopic gas sensing. The characteristics of the sensing system are directly related to various parameters of the hollow fiber. A mathematical model is proposed considering both the transmission loss of the hollow fiber and the signal-to-noise ratio of the system. Theoretical analysis is made for the dependence of the output intensity and sensitivity on the fiber parameters such as length and inner-diameter, the concentration of target gas, as well as the intensity distribution of light source. Several important results are obtained from the simulation, which provide optimizing methods for the sensing system and algorithms for error compensation.