Simple sensing head geometry using fibre Bragg gratings for strain–temperature discrimination

In this work, a simple sensing head geometry using fibre Bragg gratings for strain and temperature discrimination is presented. The sensing head geometry consists in one fibre with two FBGs bonded with a dummy optical fibre. Due to this new configuration, different strain sensitivities of the two FBGs are obtained (≈65% difference), while temperature sensitivities remain the same. This difference in strain sensitivities is substantially larger than in all previously reported dual grating sensors. The obtained experimental errors were ±13.48 με and ±2.44 °C, respectively. It is also demonstrated that this new configuration can be used as a temperature-independent strain sensor.