Research Of FBG Temperature Measurement System Based On The Demodulation Of F-P Filter

Since fiber Bragg grating came out in 1978, it has been widely applied because of its good filtering character and sensitive to temperature and strain response in the field of fiber communication, sensor, measure, etc. Fiber Bragg grating sensors have the character which the common fiber sensors have. Furthermore their prominent character is that the measuring signal is wavelength encoding, they achieve a variety of sensing (stress, temperature, strong magnetic field, etc.) by using quasi-distributed multi-point measurement conveniently. How to demodulate the wavelength encoding signal is one of the key technologies for the application of fiber grating sensors.Firstly, the naissance and development of fiber grating, the principle and application of fiber grating sensors, the actuality of wavelength demodulation At home and abroad were introduced in the paper. It analyzed the fiber grating temperature and strain sensing mechanism and discusses the cross sensitivity of fiber grating temperature– strain. Then, it carried on the simple conclusion and analysis about fiber bragg grating sensor wavelength demodulation system which has been researched by domestic and foreign.The method of the fiber grating wavelength demodulation is fiber bragg grating temperature measurement system based on F-P filter. Optical part, signal processing, temperature control part, communication part, local display, alarm output and server communication management software and so on were included in this system. The hardware and software program were designed according to the center wavelength of fiber grating, the results of FBG wavelength demodulation were displayed on the LCD or were displayed by the computer through the RS232 serial port or Ethernet interface connected the system to the computer.The floating-point DSP processing with high-performance chip was used in the high-speed digital signal processing circuit in system, DSP can realize real-time data collection computing, and address the results of the information which was processed sent to the control module through the serial port, and communicate with control module and other related modules through the GPIO interface.We tested the performance of the system, testing system, the accuracy of measuring temperature after the system built, which includes two aspects: First, the verification of accuracy of grating wavelength demodulated by system; second, the verification of accuracy of system temperature calibration. Upon examination, This experimental results obtained by this paper have some practical value.