An Optical Fiber Gas Sensor Based On Scanned-laser

Following the fast development of fiber-optic communication technologies, the fiber sensing technology has made great progress. As an important category of fiber optic sensor, the detection of gas has been great concerned. A very high accuracy has been reached by distributed feedback (DFB) laser fiber-optic gas sensor, however, due to its narrow tuning range, a wavelength of the DFB light source can only be used for measuring a specific gas, coupled with its high cost, so someone have started studying the optical fiber gas sensor based on scanned-laser at home and abroad.In this paper, by comparing the fiber-optic gas sensors based on SLED and Fabry-Perot cavity we analyzed the fiber-optic gas sensors based on scanned-lsaer. This paper proved the practical feasibility of the fiber-optic gas sensors based on scanned-laser from the measurement principle of the system, the program design of data processing, the compare of experimental results. It compared the different signal strength and the results by different algorithms of measurement. And it analyzed the influence to the system by signal strength and algorithms. They have played a positive role for practical applications. In this paper, the major work done including:1. It introduced the use of the HITRAN, demodulation methods of F-P cavity and interface functions of UA302.2. It introduced the principle of gas spectral absorption, as well as the choice of light source: It designed the experimental programs based on scanned-laser by choosing SOA as light sources respectively.3. It put up the fiber-optic gas sensor based on SLED and the F-P cavity. Take C₂H₂ as an example, experiments were done and detection curves were acquired in different light intensity and by using different algorithms.4. It designed fiber-optic gas sensor based on scanned-laser, including the design of optical path, software and hardware as well as the signal processing. And it compared with the fiber-optic gas sensor based on SLED and the F-P cavity. Take C₂H₂ as an example, experiments were done and detection curves were acquired in different light intensity and by using different algorithms. And it showed the advantage by comparing with the systems based on SLED and F-P cavity.5. It included the paper and showed the advantage of the fiber-optic gas sensors based on scanned-laser compared with distributed feedback laser fiber-optic gas sensor. It also raised the expectations of the subject.