Two-dimensional bend sensing with a single multiple-core optical fibre

The shape of a structure which is known to deform in one-dimension only can be measured using a single optical fibre with one or more sensing elements multiplexed down its length. However, to monitor the shape of a structure that can deform in three-dimensions the full vector strain, or strain field, is required. To achieve this a minimum of three fibres, embedded in a non-collinear geometry, is required.