Temperature-compensated fibre Bragg grating ‐based sensor with variable sensitivity

• A FBG strain sensor with adjustable full-scale sensitivity is proposed.
• The flexible sensor structure allows achievement of the desired measurement range.
• A simple thermal compensation technique is developed.
• The sensor performance is evaluated through tensile and temperature testing.

In this paper a Fibre Bragg Grating (FBG)-based sensor device for strain measurement with adjustable full-scale sensitivity is proposed. Installation flanges of the sensor can be moved with respect to the internal fixed FBG sensing length in order to adjust the overall strain sensitivity and the full scale measurement range of the device. Thermal drift is compensated using a technique based on the thermal expansion of a solid block connected to the fibre, in the pre-stressed region outside the grating. Typical calibration curves are reported to illustrate the sensor sensitivity variation with the layout and temperature.