Theory of waveguide propagation in randomly corrugated channels

Evolution of an emitted signal in a waveguide line is known to be highly sensitive to perturbations of lateral boundaries. Mainly depending on the size of the perturbations, there exist different evolutional scenarios for the signal. Evidently, in extremely imperfect systems where the typical height C of the surface corrugations is comparable with the average channel thickness d, the wave field is expected to be locked by a few adjacent high elevations. In this case a long-distance propagation of the signal through the waveguide is certainly out of the question. However, for telecommunication applications, the most favourable regime is exactly that, when the primary wave packet passes sufficiently long distances from a source owing to multiple re-reflections from the opposite walls. In what follows such a regime will be referred to as a waveguide propagation.