Moving near-gap solitons in the nonlinear optical medium

For a one-dimensional nonlinear optical medium with a periodic refraction i ndex, new two-parameter soliton solutions of electrodynamics equations have been found. These solutions represent two interacting waves that propagate in two opposite directions. The oscillation frequency of each wave may fal l either into the forbidden gap in the linear spectrum or outside it, and t he group velocity may vary from zero to a maximal value that is determined by the parameters of the medium. Algebraic soliton solutions have been foun d as the limit of the nonlinear solutions, when the nonlinear wave frequenc y tends to the frequency of one of the linear-spectrum branches. (C) 2000 M AIK "Nauka/Interperiodica".