Solitary Electromagnetic Waves in a Weakly Nonlinear Rhombic Waveguide Array

Abstract

Electromagnetic waves propagating along the waveguides forming a rhombic one-dimensional lattice are considered. Two waveguides that are part of the unit cell are assumed to be made of negative-index material, while the third waveguide from the same array is composed of material with a positive refractive index and has cubic nonlinearity. The equations of tunneling-coupled solitary waves spreading in each waveguide are solved. Unlike discrete solitons, the waves are localized on the axis of waveguides, and the maximum position moves uniformly along the waveguides.