A pressure mapping device with Bragg Grating sensors inscribed in bow-tie fibres

This paper presents a novel pressure mapping device, with promising applications in the medical and rehabilitation field, which is based on optical Fibre Bragg Grating (FBG) sensors embedded within a polymer sheet, and which monitors Bragg peak wavelengths on the reflected spectrum as sensing signals. Specifically, the prototype consists of a grid of 48 FBG elements, arranged in a 6-by-8 matrix way, and embedded in a 2 mm thick UV-cured polymer sheet, with a spatial resolution of 10 mm. FBGs inscribed in highly-birefringent bow-tie fibres are specifically employed in this work as the sensing elements. By means of a FBG interrogator and an optical switch, individual sensors are characterized to assess their sensing performance and to determine the pressure sensitivity. A linear pressure sensitivity up to 1.754 pm/kPa is registered based on Bragg peak shifting. Accordingly, the capability of the device for pressure mapping is tested and demonstrated by post-processing and interrogation of the acquired sensor data.