Design of Toxic Gas Measuring Instrument Using Optical Fiber Bragg Grating

Abstract

This research work aim and to design a Methane and CO gas sensor by simulating and newlinemodelling Chirped Fiber Bragg Grating (CFBG). Extensive literature survey reveals that the newlinecharacteristics of CFBG changes significantly with change in temperature and so this physical newlinephenomenon due to heat (temperature) generated during the combustion of both gases around newlineCFBG leads to estimation of concentration. newlineThe design, development and performance of Chirped Fiber Bragg Grating and its newlineapplication in gas sensing technology have been analyzed. The designed gas sensor work newlinebased on the concept of effect of temperature on grating s parameters. Techniques for gas newlinesensing employing conventional Fiber Bragg Grating have been reviewed and analyzed in newlineorder to design a gas sensor with Chirped Fiber Bragg Grating which will help to overcomes newlinethe problems associated with the existing gas sensors. newlineAnalysis and evaluation of the gas concentration by analyzed reflection intensity newlinespectrum of CFBG has been carried out. The change in reflection spectrum is analyzed with newlinesimulated results by measuring reflection coefficient, spectrum width and shift in Bragg newlinewavelength etc. Design of CFBG for gas sensing application by managing grating parameters newlinehas also been carried out which helps to analyze the gas concentration. newlineThe reflection spectrum of CFBG varies by varying the grating parameters like grating newlinelength, grating periods and refractive index due to raised temperature during Methane and CO newlinegas combustion. The sensitivity of CFBG is enhanced by coating of CFBG with Palladium for newlinemethane and Tin oxide catalyst for CO gas across the grating. Combustion of Methane occurs newlineat lower temperature due to coating of Palladium catalyst across the grating. newlineFFT(Fast Fourier Transform) iterative approach has been employed for solving the newlinenon-uniform temperature distribution from measured intensity reflection spectrum. The newlineextracted temperature distribution is characterized by amplitude, width and the central position of spectrum. newline