ИСТИНА

The problem of finding the pulse response of a thin-layered waveguide is studied. The waveguide is described by the matrix Klein-Gordon equation. The field is represented as a sum of Fourier integrals. This representation is interpreted as a contour integral on the complex manifold, that is the dispersion diagram of the waveguide. The saddle-point method is applied to the integral. All possible positions for the saddle points form the so-called carcass of the dispersion diagram. The carcass is the set of points at which the group velocity is real. We demonstrate different types of the carcass for the simplest non-trivial bi-layered waveguide. The complex branches of the carcass correspond to different types of transient pulses.