Abstract

Spatial solitons are self-trapped beams that typically occur as a result of the balance between spatial diffraction and trapping by self-induced index changes. The index changes can he caused, for example, by an intensity-dependent refractive index in a Ken-type nonlinear medium, or by pho-torefractive effects. '-² Recently the existence of solitons during second harmonic genera-lion has been observed for both one- or two-dimensional solitary waves.^iA These quadratic spatial solitons are self-guided by the strong coupling between the fundamental and second harmonic waves and, off phase-mat chng, by the self-focusing that occurs as a result of the cascaded nonlinear phase shift. Although their interactions have been calculated theoretically, no experimental work has been reported,'' Here we demonstrate experimentally the interaction between two one-dimensional (i.e., in planar waveguides) quadratic solitons. The interaction is found to be sensitive to the phase relationship between two solitary waves, similar to the Kerr case.

© 1997 Optical Society of America