FOUNDATIONS OF THEORY STEPED CYLINDERICAL OPTICAL FIBERS

The rapid introduction of fiber-optic communication lines into telecommunication networks in recent years has led to significant advantages arising from the peculiarities of the propagation of high-speed radio signals in fiber. For a deep understanding of the processes of signal transmission in fiber-optic communication lines, first of all, it is necessary to know the propagation of electromagnetic waves in fiber-optic communication lines, as well as the exact solution of electrodynamics problems. The author analyzes the propagation of hybrid electromagnetic waves in an optical fiber and defines the principles and algorithms of the engineering method for calculating the optical parameters of fibers. In the work, which consists of two parts, in the first part, the boundary value problem on the propagation of electromagnetic waves in a regular confocal cylindrical stepped fiber is solved, as a result of which: an equation of eigenvalues (EVE) is obtained, which determines the hybrid mode of propagation of electromagnetic waves, in addition, the obtained EVE is compared with similar equations obtained by other authors at the same time, the comparison shows errors or typos in their works. In the second part of the work, the analysis of the transcendental eigenvalue equation for hybrid electromagnetic waves (modes) is carried out and the critical frequencies for the corresponding modes are determined. An engineering method and an algorithm for calculating the main optical parameters of fibers optical communication line (FOCL) are proposed.