Fiber Bragg grating sensor for the measurement of elevated temperature

A novel fiber Bragg grating (FBG) sensor for the measurement of high temperature is studied. The sensing head is comprised of one FBG and two metal strips with different lengths and different coefficients of thermal-expansion (CTE). The temperature to be measured can be converted into the strain of the FBG. One can know the temperature according to the peak wavelength shift of the FBG induced by the strain. A dynamic range of 800°C and a resolution of 1°C can be obtained by this sensor system. The experiment results well agree with the theoretical analysis.