Nonlinear waves in a positive-negative coupled waveguide zigzag array

We consider the coupled electromagnetic waves propagating in a waveguide array, which consists of alternating waveguides of positive and negative refraction indexes. Due to zigzag configuration there are interactions between both nearest and next nearest neighboring waveguides exist. It is shown that there is a stop band in the spectrum of linear waves. The system of evolution equations for coupled waves has the steady state solution describing the electromagnetic pulse running in the array. Numerical simulation demonstrates robustness of these solitary waves.