Researches of initial value of the Brillouin frequency shift in optical fibers of different types

The dependence of the hyper-acoustic wave velocity on characteristics of the optical fiber core is analyzed in this article and the values of Brillouin frequency shifts for different types of optical fibers at room temperature and without strain are presented. Having database of profiles of the Mandelstam - Brillouin backscattering spectrums for different type fibers and manufacturers allow to classify the optical fibers in the optical cables and detect damaged sections of fiber optical communication line. The work was performed with the financial support of the Ministry of Education and Science of the Russian Federation (Project No. 8.9334.2017/8.9).