A pressure sensing sheet based on optical fibre technology

This paper presents a novel flexible sensing sheet, which is based on optical Fibre Bragg Grating (FBG) sensors and is capable of measuring distributed transverse loads. The device features an optical wavelength-encoded sensing signal, and it shows very promising results for pressure mapping applications. The prototype realized specifically consists of 15 FBGs, inscribed in highly-birefringent (hi-bi) Photonic Crystal Fibres (PCF) and embedded in a 2 mm thick polymer foil, which is cured by means of a customized UV polymerization procedure. The sensing elements (or taxels) are arranged over a sensing area of 30x50 mm(2), and distributed in a 3x5 matrix-like configuration; the spatial resolution is 10 mm. The taxels are first individually characterized and calibrated by conducting transverse pressure tests; a local pressure sensitivity of about 2.65 pm/kPa is registered. The sensor response to a transverse load applied over the sensing area is successively evaluated, and the results are here presented. (C) 2011 Published by Elsevier Ltd.