Vortical structure of wave caustics

Method of geometrical optics is of a great importance at calculation of wave fields in inhomogeneous surroundings. In particular, applications are extremely, interesting in correspondence with description of extending and radiation of light waves in inhomogeneous lens devices, and also in wave-guides with inhomogeneous filling, nonregular wave-guides and the wave-guides containing casual dissimilarities. Process of origin of optical caustics in a near field on a back of short cuts of multimode wave-guides is interlinked either with the transient behavior of natural modes of a light pipe, or with the diffraction location effects of the plane waves localized on surface of surroundings. The important role of the caustic surfaces in wave problems is defined by that they characterize a family of optical rays and allow estimating a pattern of behavior of field in all space of the wave guide