The Analysis of the Influence of External Factors on the Measurement Error by Sensors based on the Effect of Stimulated Mandelstam–Brillouin Scattering

This work analyzes the influence of various factors affecting the measurement error of distributed fiber-optic sensors based on the Mandelstam-Brillouin stimulated scattering effect. The mathematical model of dependence of the central frequency shift of the backscattered signal spectrum on the temperature and mechanical influences on the optical fiber is proposed. The system of equations for identification of factors affecting optical fiber is presented. Analytical relations for estimating the spatial resolving power and the maximum length of the section under test are presented. The paper presents the results of Mathcad computer simulation of the spectral components displacement in Brillouin light scattering. The functional relation between the peak frequency difference in the signal spectrum of the backscattering and the errors of the physical tension and temperature measurements is presented. Estimates of the mean square errors of measuring peak values of the spectrum are obtained. Methods of error reduction are proposed. The results of mathematical modeling of the dependence of mean square errors on the noise level, frequency sampling step and on the number of measurements are presented graphically. The methods of calculation of the mean-square errors of the measured quantities depending on the changes of parameters in the used mathematical relations are analyzed. The results obtained in the article are the basis for the metrological substantiation of the technical characteristics of the main components of fiber-optic sensors on the Mandelstam-Brillouin scattering effect.