Research On Optical Fiber Gas Detection Technology And System Implementaion Based On SLED

Development of timely and accurate manner of flammable, explosive, toxic and hazardous gas sensors for online real-time monitoring system has become primary problems to be solved in the coal, petroleum, chemicals, electricity, transportation, aerospace and other fields of environmental monitoring. In recent years, with development of the optical fiber sensing technology, optical fiber gas sensors have received wide attention at home and abroad.The thesis takes methane gas which is the main component of coal mine as the target gas, and studies and establishes the methods based on optical absorption gas detection system. The system has high sensitivity, fast response, large dynamic range, flame proof, anti-electromagnetic interference and etc. By the theoretical analysis of near-infrared selective absorption of the gas, the thesis put forward the theoretical basis for measuring gas absorption. Through the analysis of methane absorption spectrum chart, select the appropriate absorption peak suitable for secondary low-loss silica fiber for long distance transmission.The thesis describe differential absorption gas detection and harmonic detection principle, establish the mathematical principles of the two test model, and bring forward the appropriate system design. In this article GRIN chamber combined with SLED light source compose a distinctive design of the optical system. The micro-displacement platform was controlled by the stepper motor to adjust the two F-P standards。In this article GRIN chamber combined with SLED light source compose a distinctive design of the optical system. The micro-displacement platform was controlled by the stepper motor to adjust the two F-P horizontal distance .It realizes the honeycomb filter to pass the spectrum to aim at the gas absorption spectral line wave length and the reference wave length alternately, develops the difference absorption technology to apply in the weak gas detection technology.The paper has carried on gas detection system's overall experiments including the characteristic parameter experiment, the gas absorption experiment and the experiment compared to test the value and so on. The experimental result and the data analysis have confirmed the spectral absorption type optical fiber gas sensing detection system design plan feasible and accurate.