Ccd Spectral Imaging Technology In Fiber Grating Demodulation Technique

Fiber Bragg Grating (FBG) sensor has the characteristics of anti-electronmageticinterference, the resistance corrosion, the high sensitivity and so on, so it is one of thecurrent hot research fields in the optical fiber grating sensor technique fields. Now It iswidely applied in many fields such as the structure monitoring of the large compoundmaterial and the concrete, electric power industry, medicine, chemical engineering etc.The demodulation technique of the FBG is currently a critical and difficult problem forthe application of FBG sensoring technique.Based on analysis of domestic and foreign study actualities on FBG anddemodulation technique for FBG in the paper, the principle and the method of thespectrum imagery technology to use in the optical fiber grating demodulation are depplystudied. The system of optical fiber grating wavelength demodulation is established byusing the linear CCD(Charge Coupled Device)spectral imagery law.Based on analysis of the spectral imaging theory, each optics element of thespectral imaging system is designed. According to CCD application in the micro opticalfiber spectrometer, by selecting the dispersion element properly, one kind ofminiaturized structure spectrum demodulation system has been desigined.The raytracing and test are realizde with Zemax software. Acording to the conclusion, theparameters of optics element fitting the optical fiber grating demodulation system aredesigned. Using new type Field Programmable Gate Array(FPGA), the linear CCDTCD1500C driver circuit is designed, we put the FPGA to configure 32 bit CPU byusing the Quartus software and make it used in measuring data processing. Thus a newtype high integrated spectrum imagery data acquisition system is realized.The wavelength demodulation simulating experiment is carried on by using thetunable semiconductor laser. By tuning the laser output wavelength, simulating thereflection Bragg wavelength shift, has confirmed the theoretical analysis result and laidthe experimental foundation for realizing miniaturization of the optical fiber gratingdemodulation meter of spectrum imagery law. In the paper the resolving power of thewavelength demodulation system is analysised, the primary factors affecting the resolving power of the instrument have been discussed detailedly, the methd ofenhancing the resloving power is proposed, too. Collected datum are processed andanalyzed by applying Origin software. Through studying the demarcating method of thesystem of spectral imagery wavelength demodulation, a demarcating method whichsuits to the system of spectral imagery wavelength demodulation is given. Thus thepracticality foundation of the system of spectral imagery wavelength demodulation isestablished.