Study on strain and temperature cross sensitivity of fiber Bragg grating sensor

The cross sensitivity of strain and temperature is a key problem for fiber Bragg grating (FBG) sensors. Based on the physical mechanism of the strain and temperature cross sensitivity, several schemes for the discrimination measurement of temperature and strain are presented. They are dualwavelength matrix, two FBGs with different cladding diameters and chirped Bragg grating techniques. Based on dual-wavelength matrix technique, a new structure of FBG sensor based on an elastic strain-sensitive element is proposed. Simultaneous discrimination measurements of the pressure and temperature are demonstrated in 20MPa and 150℃, and its temperature sensitivity is 0.02nm/℃.