Ray dynamics in waveguide media exhibits chaotic motion. For a finite length of propagation, the large distance asymptotics is not uniform and represents a complicated combination of bunches of rays with different intermediate asymptotics. The origin of the phenomena that we call “chaotic transmission,’’ lies in the nonuniformity of the phase space with sticky domains near the boundary of islands. We demonstrate different fractal properties of ray propagation using underwater acoustics as an example. The phenomenon of the kind of Levy flights can occur and it can be used as a mechanism of cooling of signals when the width of spatial spectra dispersion is significantly reduced.

Chaotic transmission of waves and “cooling” of signals

An investigation is made of the statistical properties of an optical field with a speckle structure in multimode fiber waveguides. Asymptotic formulas are obtained for the spatial correlation function of the field. This function is used to obtain expressions for the statistical average density of dislocations in the wavefront of the field distributed over a transverse cross section of a waveguide with an arbitrary refractive index profile. It is shown that the dislocation density is an oscillatory function of the transverse coordinate. A study is also reported of the dependence of the dislocation density on the refractive index profile and on the conditions of excitation of a waveguide.

S S Abdullaev

Papers

Speckle structure of an optical field in multimode fiber waveguides