Arbitrary strain profile measurement within fibregratings using interferometric Fourier transformtechnique

Abstract

An interferometric Fourier transform technique of measuring arbitrary strain profiles within intra-core fibre Bragg gratings is described and demonstrated. Using an ~86 mm long grating sensor, measurement of the strain field along a non-uniform cross-section cantilever beam was made. A theoretical strain accuracy of ~25 µɛ is possible with an achieved spatial accuracy of 2.58 mm.