Temperature-insensitive fiber Bragg grating high-pressure sensing technology

In order to achieve pressure measurement by single fiber Bragg grating (FBG), a novel FBG high-pressure sensor was designed, which was insensitive to temperature. The pre-ssure and temperature responses of the sensor were researched. First, the configuration and package of the sensor were presented. Then the temperature-insensitive principle was analyzed theoretically. The relationship between the central wavelength of FBG and the pressure was deduced, and the analytical expression of pressure sensitivity is given. Finally, the temperature response and pressure response of the sensor were analyzed by experiment. Experimental results show that the temperature compensation is achieved within the temperature range of 21℃ to 260.8℃, the average wavelength shift is 0.75pm/℃, and the pressure response sensitivity of -0.054 8 nm/MPa is obtained in 0~44 MPa, which is 18.27 times higher than that of the bare FBG. The pressure response of FBG sensor has good linearity and repeatability, the experimental results agree with the theoretical one, which indicates that the sensor can achieve precise measurement of pressure by single FBG.