Analysis and Correction Method of Axial Strain Error in Multi-core Fiber Shape Sensing

The shape sensing technology based on multi-core fiber is attractive for many applications. A particularly important problem needing to be addressed is minimizing possible errors in shape sensing. In this paper, one of sensing errors, namely the axial strain error of multi-core fiber in shape sensing is investigated. A model of the axial strain error is established with the theoretical analysis. Furthermore, a correction method for axial strain error using measured data obtained from fiber Bragg gratings sensors is developed. In order to validate the correction method, the twist experiment of a seven-core fiber is carried out. All calculated strain values are processed using curve fitting analysis. The characteristics of the corrected data fitting present good sinusoidal properties and confirm the theoretical analysis well. The results show that the mean R2 of the fitted strain values after the correction is 0.9578. The feasibility of the proposed method is verified by experimental results.