A fibre optic pressure sensor based on the application of a transverse load ontoan epoxy-resin material embedded over a sub-section of a fibre Bragg grating(FBG) is presented. When a transverse load is applied to the epoxy material itdeforms and transfers the load onto the optical fibre in the form of an axialstrain that changes the period of the FBG over the embedded region. Thisintroduces a phase shift between the two resulting identical gratings that lieeither side of the loaded section, creating a spectral drop-out within thebandwidth of the FBG. A 2 mm section at the centre of FBGs of length 6 mm,recorded in both single mode and highly linearly birefringent optical fibres,was embedded in resin, and were subsequently subjected to a transverse load. Theloading technique, while offering protection to the optical fibre frommechanical damage, enhances transverse load sensitivity, without introducingbirefringence.
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