Fiber Bragg Grating Strain Measurements Of Temperature Separation And Compensation Study

In this paper, the temperature separation and compensation of FBG which takes the strain measurement are further researched. The main work is as follows:To resolve the cross-sensitive issue of temperature and strain, four programs of temperature separation and compensation are designed. The combination of Bragg grating and long-period is used in the first three programs. The first three programs take advantage of the long-period grating temperature characteristic of high sensitivity and avoid some adverse problem. In addition, the 1st and the 3rd program only need a set of light source and a set of demodulation system. The combination of two Bragg gratings is used in the fourth program. Due to the different angle of two Bragg gratings, the strain sensitivity of the fourth program is also different. When the angle of two Bragg gratings is 90, the strain sensitivity is the highest.At last, the calibration experiment of temperature and strain of Bragg grating and the fourth program experiment are finished. From the calibration experiment, we know that fiber Bragg grating has a very good linear response to temperature and strain, and the temperature sensitivity coefficient is 0.011nm/℃, and the strain sensitivity coefficient is 0.0016nm/με. From the fourth program experiment, we know that this program effectively compensates the temperature and eliminates the serious impact on the reflection wavelength shift of fiber Bragg grating caused by the temperature changes when fiber Bragg grating measures the strain, and it proves the feasibility of the 4th program.This is the basic research work of the project of testing strain transient in the barrel by using the fiber Bragg grating, in the process of the high-speed artillery shells firing in the barrel, the barrel is injected in a powerful current, and the barrel temperature increases in a blink rate, so the elimination of the impact of temperature on the fiber grating which is studied in this paper is particularly important. We have obtained very important results from the series of experiments on testing the strain, using the fiber Bragg grating with the non-equilibrium optical M-Z interferometer as its demodulation system. We have laid a good foundation for the further transient testing work.