Flat multi-core fibre for twist elimination in distributed curvature sensing

Abstract Optical fibre sensors offer many advantages in comparison to their conventional counterparts, such as extremely low sensitivity to external electro-magnetic fields and small dimensions. The multi-core fibres in particular are ideal candidates for shape sensing due to the intrinsic 3D coordinate system they offer. However the twist of the multi-core fibre during its deployment along the structure of interest, distorts the 3D coordinate system based on their fixed position. In this work a multi-core fibre of unique geometry is presented as a solution to this issue. Owing to its two flat sides, this fibre presents enhanced preferential bending that eliminates the random twist of the sensing fibre.