The Design And Research Of Refractive Index Modulation Of Optical Fiber Gas Sensing System

It is the accident rate locations in the explosion and fire hazard atmospheres. It does harm to the social security, the environment, people's lives and property and national security. It is necessary to establish a scientific and rigorous safety testing and real-time management system. It not only can be effective in preventing accident, but also avoids environmental pollution, casualties and economic losses. It is imperative to research sensor applied in the explosion and fire hazard atmospheres. Currently, optical fiber gas sensing technology has been proven to be an effective method of gas detection in the explosion and fire hazard atmospheres.In the present work, it studies the basic methods of safety testing in the explosion and fire hazard atmospheres and introduces the principle and categories of the optical fiber sensing technology. On the basis of this paper, the refractive index modulation of optical fiber gas sensing system. The optical fiber gas sensing system has characteristics such as a simple structure, low cost, convenient operation and so on. According to the existing laboratory equipment and experimental conditions, We do experimental research and long-time observation in the field (outdoor air) with the refractive index modulation of optical fiber gas sensing system. The results that the fiber gas sensing system has the high sensitivity, stability, and good repeatability show a good application in the field. It is effectively verified the feasibility of the system. The paper will be divided into the following five chapters:First of all, the optical fiber sensing technology and its features---intrinsic safety, and the optical fiber gas sensing technology, the classification of research methods were introduced. Then refractive index modulation of optical fiber gas sensing system was described.Second, the theories of the fiber propagating light and refractive index modulation of optical fiber gas sensing system were introduced. The gas-sensitive optical film was described in detail and the technological process of gas-sensitive thin film and technology and the development process of gas-sensitive materials were sketched out.Third, the design of optical gas sensing system based on distributed-feedback (DFB) semiconductor laser was developed and described. The contents include:the choice of light source, experimental introduction of the main instrument performance and the design of micro-optical sensing unit which was spontaneous developed successfully.Fourth, the research and analysis of the optical fiber gas sensing system which was devised were introduced. The spectral characteristics of semiconductor laser emission analysis, and the optical fiber loss was tested. At last, the fuel gas was detected and did outdoor long-term observational study to have a very good effect.Finally, the refractive index modulation of optical fiber gas sensing technology is used in an explosion and fire hazard atmospheres, and the problems of the system need to be resolved. The research interests of optical fiber gas sensing technology used in the explosions and fire hazard atmospheres need to be put forward. System integration, intelligence, networking, miniaturization have to be advanced.