Vol. 19, issue 02-03, article # 30

Abstract:

The system of evolutionary differential equations describing the propagation of radiation in optical bundles with the allowance for the coefficients of coupling between the fibers is obtained. It is shown that, in optical bundles consisting of single-mode fiber elements, the field amplitude in bundle cross section satisfies the parabolic (diffusion) or Helmholtz equation, in which the diffusion coefficient is determined by the distance between the centers of fiber cores and by the overlap integral of interacting modes. For few-mode and multimode fiber channels, the system of equations can be solved by the method of splitting into physical processes. The problem of the influence of adiabatic (conic) increase of the fiber core radius on the contrast in the spatially unsteady regime is considered. Based on the model of pairwise interaction of the fibers, the parameters of the transfer function in optical bundles are calculated from the analysis of cross talk. The influence of polarization corrections to propagation constants of simple fiber on the parameters of the transfer function is estimated from the results of numerical calculations.