Abstract

The existence of simultons (mutually trapped solitary waves with different carrier frequencies) in quadratic media was predicted two decades ago [1], However they attracted renewed interest also in view of recent successful experimental observation [2]. In second-harmonic generation (SHG) different simulton families, sustained by the interplay of dispersion (or diffraction) and nonlinearity, propagate either as bright-bright pairs or dark-dark ones [3]. Here we show that when the interaction is dominated by group-velocity difference or spatial walk-off (ie, whenever z_w ≪ z_d, where z_w, z_d are the walk-off and dispersion length, respectively) new exact simultons exist as pairs of dark (harmonic) and bright (fundamental) envelopes which propagate with a locked group-velocity.

© 1996 Optical Society of America