A Novel Method of the Brillouin Gain Spectrum Recognition Using Enhanced Sobel Operators Based on BOTDA System

Abstract

Enhanced Sobel operators were proposed to identify the scattering spectrum based on a Brillouin optical time-domain analysis (BOTDA) system and experimentally demonstrated. To the best of our knowledge, this is the first time to use the enhanced Sobel operators in the BOTDA system. The proposed approach regarded the Brillouin scattering spectrum as an image, where the Brillouin gain could be regarded as edges of the image, the Brillouin gain spectrum was sharpened more, and better denoising effect was achieved by the enhanced Sobel operators. Not only that, the novel method could omit the Lorentz fitting and make scattering spectrum recognition more intuitive and fast regardless of fitting multiple points caused by different temperatures or strain along the different positions of the fiber. We successfully realized the recognition method over a 14-km single-mode fiber with 10-m spatial resolution and obtained the temperature at 61.4°C of the heated water, compared with the consequence (61.4°C) of Lorentz curve fitting without much sacrifice of the sensing accuracy.