Simultaneous independent measurement of temperature and strain using a tilted fibre Bragg grating

A single fibre Bragg grating is used to discriminate between temperature and strain by exploiting the core-cladding mode coupling of a tilted fibre Bragg grating (TFBG). The core and cladding modes exhibit different thermal sensivities, while the strain sensivities are approximately equal. Monitoring the core-core mode coupling resonance and the core-cladding mode coupling resonance within the spectrum of a single TFBG allows the separation of the temperature and strain induced wavelength shifts.