Solitary-wave interactions in quadratic media near type I phase-matching conditions

The interaction between two optical soliton beams during type I second-harmonic generation in quadratically nonlinear materials has been investigated numerically. The product of the interaction is found to be highly sensitive to the relative phase between the launched beams. Threshold phenomena were found that persisted even when the input beams were only approximately solitary waves. Cases of both small and large collision angles were investigated, and the effect of walk-off was also taken into account. (C) 1997 Optical Society of America.