  The theoretical study of the optical properties of TE- and TM- modes in a
four-layer structure composed of the magneto-optical yttrium iron garnet
guiding layer on a dielectric substrate covered by planar nanocomposite guiding
multilayer is presented. The dispersion equation is obtained taking into
account the bigyrotropic properties of yttrium-iron garnet, and an original
algorithm for the guided modes identification is proposed. The dispersion
spectra are analyzed and the energy flux distributions across the structure are
calculated. The fourfold difference between the partial power fluxes within the
waveguide layers is achieved in the wavelength range of 200 nm.
