A Single Fiber Bragg Grating Sensor for the Simultaneous Measurement of Strain and Temperature

In this paper, we have introduced the bandwidth of a Tilted Fiber Bragg Grating (TFBG) as a measurand and combine it with the central Bragg wavelength to address its cross-sensitivity with temperature and strain. We have developed a method for coating the TFBG with a thermochromic material and characterized the coated TFBG sensor under temperature and strain variations. We observed that the spectral bandwidth is sensitive only to the temperature change while the central Bragg wavelength is sensitive to both the strain and temperature. Therefore, we can measure the temperature from the TFBG bandwidth alone and measure the strain from the TFBG central wavelength after compensating for temperature induced wavelength change.