Experimental study on cross-sensitivity of temperature and strain of fiber optic Bragg gratings

The strain response of fiber Bragg grating sensors was measured at a constant temperature. Strain sensitivity coefficient and cross-sensitivity coefficient were obtained at temperatures from -150°C to 550°C. It is found that the two kinds of strains are the functions of temperature. The strain coefficient will slowly decrease with temperature increasing at higher temperature, and the cross coupling effect is not obvious; the strain coefficient will increase with temperature decreasing at lower temperature, and the cross coupling effect becomes obvious. In addition, the wavelength shift of fiber Bragg gratings changes linearly with applied tensile strain within 6000 με at a constant temperature.