CAJ | 학술논문

综合应用取样光纤光栅滤波和改进的差分吸收检测技术,实现了对甲烷气体等距分布的多条近红外吸收线的同时测量,完善了差分吸收技术应用于弱气体检测的理论.基于分子光谱学理论对谱带精细结构的分析,结合取样光纤光栅的梳状滤波思想,以1.66μm附近甲烷泛频(2v3)吸收光谱R支中的R4线为中心,同时对R3、R4和R5三条吸收线进行测量.为消除光源功率波动对测量结果的影响,利用两个同类型的取样光纤光栅实现对气体浓度的差分吸收检测.选用中心波长在R4附近的啁啾光纤光栅作为光学带通滤波器,利用PIN PD实现对三条吸收线处光强的同时测量,由比值处理消除光源功率波动对测量结果的影响.通过实验验证了系统的可行性.
종합응용취양광섬광책려파화개진적차분흡수검측기술,실현료대갑완기체등거분포적다조근홍외흡수선적동시측량,완선료차분흡수기술응용우약기체검측적이론.기우분자광보학이론대보대정세결구적분석,결합취양광섬광책적소상려파사상,이1.66μm부근갑완범빈(2v3)흡수광보R지중적R4선위중심,동시대R3、R4화R5삼조흡수선진행측량.위소제광원공솔파동대측량결과적영향,이용량개동류형적취양광섬광책실현대기체농도적차분흡수검측.선용중심파장재R4부근적조추광섬광책작위광학대통려파기,이용PIN PD실현대삼조흡수선처광강적동시측량,유비치처리소제광원공솔파동대측량결과적영향.통과실험험증료계통적가행성.
A novel fiber-optic methane detection system was proposed based on sampled fiber bragg grating ( SF-BG) filtering technique. By means of SFBG, Near-infrared equal-spaced multi methane absorption lines were de-tected simultaneously and difference absorption detection theory was developed. The fine structure of methane ab-sorption spectra was analyzed. Using the comb filter characteristic of SFBG, R3, R4 and R5 lines in 2υ3 overtone band around 1.66 μm were measured at the same time. In order to diminish the influence of light source instability on measurement result, two SFBGs of same type were used alternately to fulfill the task of difference absorption de-tection. Chirped fiber grating with its central wavelength around R4 was adopted as optical band-pass filter. The light power corresponding to three absorption lines and three reference wavelengths was detected simultaneously by PIN PD. The influence of light source instability was avoided by ratio treatment and the validity of the system was verified by experiments.