We report on existence and properties of discrete gap solitons in zigzagarrays of alternating waveguides with positive and negative refractive indices.Zigzag quasi-one-dimensional configuration of waveguide array introduces strongnext-to-nearest neighbor interaction in addition to nearest-neighbor coupling.Effective diffraction can be controlled both in size and in sign by the valueof the next-to-nearest neighbor coupling coefficient and even can be cancelled.In the regime where instabilities occur, we found different families ofdiscrete solitons bifurcating from gap edges of the linear spectrum. We showthat both staggered and unstaggered discrete solitons can become highlylocalized states near the zero diffraction points even for low powers.Stability analysis has shown that found soliton solutions are stable over awide range of parameters and can exist in focusing, defocusing and even inalternating focusing-defocusing array.
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