Research On Brillouin Spectrum In Reconstruction By LM Algorithm

Stimulated brillouin scattering technology available spectrum from since its unique nonlinear effect and extensive application in optical fiber sensing, Marine water quality monitoring,underwater laser radar detection, atmosphere, water monitoring system. But in actual testing brillouin scattering spectra information is easy to loss or wrong. So,it has a broad prospect for how to effectively will brillouin spectrum information to improve the reconstruction of the real out stimulated brillouin scattering spectra and application of technology.The main content of this paper is to study for:The first step, analyzes the main application of optical spectroscopy at home and abroad research and development trends and research spectrum reconstruction technique of purpose and meaning; The second step, this paper introduces the experimental used in the spectral reflectance basic knowledge and brillouin scattering spectrum of the mathematical model; the third step, because the LM algorithm converges fast, convergence stable performance is good, can meet the requirements of the system, as the experiments LM algorithm of spectral reconstruction algorithm, this paper analyzes the basic theory of the LM algorithm and how to adjust algorithm of key ratio, this paper expounds the LM algorithm mathematics theory model and general iteration step, the application of this algorithm can effectively improve the spectral reconstruction stability and precision of the system. The paper proposes the MATLAB program operation environment realize spectrum rebuilt,then establish experiment system, it procees brillouin spectrum reconstruction in theory under the condition with the LM algorithm and MATLAB running environment, then it was used respectively to FBG and two single FBG parallel of the gain of experimental data, to reconstruct the fiber Bragg grating reflection of au spectrum and the petronas twin fitting optical fiber Bragg grating reflection spectrum, get effective spectrum information and reconstruction results, so fully prove compare LM algorithm is applied to optical fiber Bragg grating reflection spectrum of reconstruction correctness and feasibility, further proof that the model makes the LM algorithm is applied to brillouin scattering spectra feasibility and correctness of the reconstruction,and produced in the paper analyses the error for the experimental results. Experiments show that it has small errors, high accuracy, good mirrors the real brillouin scattering spectrum information after comparing brillouin scattering spectrum reconstruction information after LM algorithm iterative with the actual situation of the brillouin scattering information.