Optical Fiber Detection Of Volatiles Based On The Sensitive Membrane

Detection of the volatiles is a technology which widely used in modern industry and environment protection.Combination of the optical fiber sensing is a major research direction for volatile organic compounds measuring.This thesis is aim to research the optical fiber detection of VOCs based on the sensitive membranes.We proposed two kinds of sensitive membranes in VOCs detection and achieved the multiple point and mixed gas VOC detection by combining with the optical fiber sensing technology.The main contents are as follows:1.We proposed and achieved the high sensitivity optical fiber VOC sensor based on zeolite film.We synthesized the zeolite film on optical fiber flat end-face,which constituted the Fabry-Perot interference.The detection sensitivity is 2.78×10^-3 d B/ppm-1.23×10^-3 d B/ppm in the concentration range of 350 ppm-5250 ppm.2.We proposed and improved the spherical fiber end surface VOC sensor based on zeolite film.We synthesized the zeolite film on optical fiber spherical end-face,which constituted the arc-shaped Fabry-Perot interference cavity.The detection sensitivity is 0.91 nm/ppm in the concentration range of 0-70 ppm.3.We proposed a multiple points VOC detection system based on zeolite film with aid of arrayed waveguide grating.We achieved the multiple points measuring sensitivities range from 0.015 d B/ppm to 3.9×10^-3 d B/ppm in the concentration range of 0-550 ppm.4.We proposed two optical fiber VOCs sensors based on PDMS,achieved the detection of two different VOCs concentration,and verified the performance in responding the temperature change.5.We proposed and achieved a VOC detection system with two PDMS based sensors.According to different sensitivities to ethanol and isopropanol,the system achieved distinguishing the mixed gas containing two kinds of VOC based on the linear matrix algorithm.