The Application Of Infrared CCD To The Fiber Bragg Grating Demodulation System

Fiber Bragg Grating(FBG) Sensor has the characteristics of anti-electromagnetism interference, the resistance corrosion, the high sensitivity and so on, so it is one of the current hot research fields in the optical fiber grating sensor technique fields. Now it is widely applied in many fields such as the structure monitoring of the large compound material and the concrete, electric Power industry, medicine, chemical engineering etc.Firstly, the recent developments in the area of optical fiber grating sensors are reviewed. The method of fiber grating fabrication is introduced briefly. And also introduces FBG demodulation methods, such as grating matching method, non-balance Mach-Zehnder interferometer method. Based on analysis of domestic and foreign study actualities on FBG and demodulation technique for FBG in the paper, the principle and the method of the spectrum imagery technology to use in the optical fiber grating demodulation are deeply studied. And set up a system of optical fiber grating wavelength demodulation established by using the linear infrared CCD (Charge Coupled Device).Based on analysis of the spectral imaging theory, on the basis of the construction and principles of dispersive spectrometer, introduces the components of dispersive spectrometer such as dispersive system, imaging system and receiving system as well as characteristic parameter. On the basis of theoretical analysis, we choose the symmetrical Czerny-Turner optical path system, and each optics element of the spectral imaging system is designed. According to CCD application in the micro optical fiber spectrometer, by selecting the dispersion element properly, one kind of miniaturized structure spectrum demodulation system has been designed. The ray tracing and test are realized with Zemax software. According to the conclusion, the parameters of optics element fitting the optical fiber grating demodulation system are designed.In the paper the resolving power of the wavelength demodulation system is analysis, the primary factors affecting the resolving power of the instrument have been discussed detailed, and the method of enhancing the resolving power is proposed, too. Through studying the demarcating method of the system of spectral imagery wavelength demodulation, a demarcating method which suits to the system of spectral imagery wavelength demodulation is given. Thus the practicality foundation of the system of spectral imagery wavelength demodulation is established.At last, temperature demodulation experiment is done to validate this solution. The tests indicate that the whole system has an excellent accuracy and reliability.