基于波长调制技术的近红外甲烷检测仪  

Near-infrared CH_4 detection device using wavelength-modulation technique

作　　者：黄渐强[1] 翟冰[1] 叶玮琳[2] 郑传涛[1] 王一丁[1] 

机构地区：[1]吉林大学电子科学与工程学院、集成光电子学国家重点联合实验室吉林大学实验区,吉林长春130012 [2]汕头大学工学院,广东汕头515063

出　　处：《光电子．激光》2014年第5期947-953,共7页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61307124);国家科技支撑计划项目(2013BAK06B04);吉林省科技发展计划(20120707,201101036);长春市国际合作项目(11GH01);广东省教育厅育苗工程项目(2013LYM_0030);汕头大学科研启动基金(NTF12022);汕头大学青年科研基金(YR12005)资助项目

摘　　要：为了在煤矿环境中实时检测甲烷（CH_4），利用中心波长为1．654μm的分布反馈（DFB）激光器，基于可调谐激光二极管吸收光谱法（TDLAS），实验报道了一种近红外（NIR）CH4检测仪。为了驱动DFB激光器并从差分信号中提取二次谐波信号，自主设计了激光器智能温度控制器、激光器扫描和驱动电路以及高性价比的锁相放大器，对各模块的性能做了测试和表征。利用各光学模块和电学模块，对系统进行了集成；为了得到其检测性能，开展了详细的CH_4检测实验。结果显示，在O～100％的浓度范围内，相对测量误差小于7％，最小检测下限（MDL）为1．1×10-5。对两种标准浓度气体样品（浓度为1×10-3和2×10-1）的24h浓度测量结果表明，检测仪具有较好的稳定度，两组测量结果较真值的波动范围分别小于7．0％和2．5％。利用相似的检测机理和相同的硬件系统，通过更换其他波长的激光器，本文检测仪也可实现对其它气体的检测。In order to realize real-time detection of CH4 under coal-mine environment,by using a wave- length-modulated distributed feedback （DFB） laser whose wavelength is centered at 1. 654 μm,a stand- alone near-infrared （NIR） CH4 detection device is experimentally proposed based on tunable diode laser absorption spectroscopy （TDLAS） technique. An intelligent temperature controller, a scan and modula- tion module and a cost-effective portable lock-in amplifier are developed to drive the DFB laser and ex- tract the second harmonic signal from the differential signal between the two channels, and their per- formance is thoroughly measured and characterized. The device is integrated with all optical modules and electrical modules, and measurements are carried out to study its detection performance on CH4. Experi- mental results show that the relative detection error is less than 7 % within the detection range from 0 to 100% ,and the minimum detection limit （MDL） is about 1.1× 10-5. Long-term monitoring lasting for 24 h on two standard gas samples （1× 10-3 and 2× 10-1 ） suggest good stability,whose maximum de- tection errors are smaller than 7.0 % and 2. 5 %, respectively. With similar detection principle and the same hardware system in this paper,this device can also be used for other gasesr detection by utilizing a different DFB laser with the corresponding absorption wavelength.

关 键 词：红外(IR)检测 近红外(NIR) 甲烷(CH_4)检测 波长调制 

分 类 号：TH83[机械工程—仪器科学与技术]