We numerically investigate the stability of one- and two-dimensional gap solitons for very long propagation distances both in self-focusing and in self-defocusing nonlinear photonic media. We demonstrate that the existence of stable solitons in the first gap requires much stronger lattices in a self-focusing than in a self-defocusing medium. Moreover, we present a one-dimensional linear stability analysis of the fundamental solitary mode in the first gap considering a self-focusing photorefractive nonlinearity.

• Received 31 August 2006

DOI:https://doi.org/10.1103/PhysRevE.75.016601