多通道扫描型红外光纤气体测量系统研究

Study on the multi-channel scanning fiber-optic infrared spectrum system for measuring gas concentration

提出了一种将声光可调滤光器技术应用于气体浓度测量的红外光谱系统.该系统以氙灯作为光源,TeO2晶体作为声光介质的色散元件,InGaAs光电二极管阵列作为多通道检测器,利用光纤探测和传输光信号,由计算机处理数据和显示结果.通过声光调制将宽带光变为单色光,通过超声射频的变化实现光谱扫描,可对不同气体进行快速测量,无机械调谐机构,结构简单.通过对甲烷气体的实验表明,该系统的有效光谱测量范围为900～1900nm,光谱分辨率为60nm,可用于对有害气体的在线检测.

An infrared（IR） spectrum system for measuring gas concentration is presented based on the technique of acoustooptic tunable filter （AOTF）. In this system a xenon lamp as the light source of the broadband spectrum was used, an AOTF as dispersive element which used TeO2 crystal as interaction mediums was applied, an InGaAs PIN PDA was selected as a multichannel detector, the optical fibers were utilized to probe and transmit light, a computer was utilized to process and display the results, The system changed broadband light into homogeneous light by acousto-optical modulation, realized spectrum seannig through varying the ultrasonic driving frequency, Quick measurement of different gases was attained. It had no mechanical tunable components, the structure is simple. The experimental results of CH4 show that its effective measuring range is 900- 1900nm, and the spectral resolution is 60nm, it can be applied to on-line detection of harmful gases.