In the framework of second-harmonic generation with type I phase matching, we investigated the role played by temporal or spatial walk-off. Using a variational technique, we found that a two-parameter class of solutions always exists, even when nonnegligible spatial or temporal walk-off is present. We checked solitonlike behavior for the approximate stationary solutions by numerical integration of the governing equations; expressions of phase condition for stationary solutions and velocity of the locked waves were derived. To outline the possibilities offered by our approach in predicting the behavior of χ<sup>(2)</sup> devices, several examples for beam and pulse propagation in KTiOPO<sub>4</sub>and LiNbO<sub>3</sub> are presented.
© 1997 Optical Society of America
A. D. Capobianco, B. Costantini, C. De Angelis, A. Laureti Palma, and G. F. Nalesso, "Role of walk-off in solitary-wave propagation in materials with quadratic nonlinearity," J. Opt. Soc. Am. B 14, 2602-2609 (1997)