Reconstruction of strains with a non-smooth distribution using optical fiber Bragg grating

Abstract

The paper presents a reconstruction of strains with a non-smooth distribution affecting the optical fiber Bragg grating based on its reflection intensity spectrum. The reconstruction was performed for a grating strained along 0.25, 0.5 and 0.75 of its length. The transition matrix method and the Nelder-Mead nonlinear optimization method were used for this purpose. The results of simulations and reconstruction of the strain profile indicate good consistency with the original strain profiles. Reconstruction errors of these profiles are within the single digit percentage range. For a grating strained along 0.5 or 0.75 of its length, the error does not exceed 0.34% when the reconstruction is based on a simulated reflection spectrum; the use of a measured spectrum results in an error of up to 2.2%.