Simultaneous measurement of strain and temperature using single tilted fibre Bragg grating

Tilted fibre Bragg grating (TFBG) with grating planes tilted at an angle of 3deg corresponding to the fibre axis shows core mode and a large number of cladding-mode resonances in its transmission. Discriminating temperature and strain simultaneously using a single tilted fibre Bragg grating is proposed and demonstrated experimentally. The wavelength shifts of the TFBG in response to temperature and strain are investigated. The results show that the cladding modes and core mode have different strain sensitivities while the temperature sensitivities are equal. So, it is possible to monitor the core-mode resonance and the cladding-mode resonances of the TFBG spectrum, allowing the separation of the temperature and strain induced wavelength shifts.