Calibration method for fiber bragg grating temperature sensor

A successful nonlinear calibration method for fiber Bragg grating (FBG) temperature sensor system based on wavelength-division multiplexing was proposed and demonstrated theoretically and experimentally. In consideration of the nonlinear relation between FBG center wavelength and temperature due to thermal expansion and thermo-optic effect, linear and nonlinear curve fittings were used to evaluate the measurement errors in data processing respectively, measurement errors were calculated. As a result, the maximum error is reduced from 0.15 degC to 0.08 degC when the temperature is in the range -5 degC to 35 degC. Experimental result shows that nonlinear calibration method achieved a higher precision.