The Research On Demodulation Technology Of Fiber Bragg Grating

Fiber Bragg grating is a critical breakthrough after adulterate ER fiber amplifier in recently years. It is widely applied in fiber communication, fiber sensing and light signal sensing fields. With the development of write-in technology of fiber grating, its applications more and more, fiber grating is one of the most rapidly development and most representative fiber reactive devices.Sensor based on Fiber Bragg grating is a wavelength modulation sensor, which obtains sensing information through modulation of Bragg center wavelength by outside parameters. In the currently technical condition, the wavelength demodulation technology of Fiber Bragg Grating is a critical and difficult problem in recent research. Developing high precise and low price demodulation instrument is the key problem for Fiber Bragg Grating widely applied in practice.With the research of Fiber Bragg Grating matched demodulation, a method of matched demodulation of Fiber Bragg Grating based on microcontroller technology is introduced in this paper, and AT89S52 is used as the central processing chip. The matched fiber grating, which is matched by sensing fiber grating, is forced by step-by-step motor with microprocessor control. Therefore it realizes measurement of varieties of outside physical parameters and reaches the goal of demodulation in the end. In the paper the main research contents as follows:(1) The basic principle and main characteristics of Fiber Bragg Grating are introduced in this paper. The theory of fiber grating sensing is studied systematically.(2) Many classical FBG demodulate methods are outlined and their advantages and disadvantages are compared. On the basis of principle research on fiber grating match, matched demodulation method of fiber grating based on microcontroller is put forward with practice. And the demodulation experimental system is built.(3) The light path and circuit of the hardware system of demodulation method are designed and chosen for parameters. The software system is designed. (4) The matched demodulation system method is applied in the stress measurement. The sensing and demodulation experiments are studied, and the experimental results are processed and analyzed. So it verifies the correctness of this method.(5) On the basis of physical analysis and experimental research, the advantages and disadvantages of this method are summarized, and some improving methods are proposed.