Spatial modulational instability and multisolitonlike generation in a quadratically nonlinear optical medium

A novel type of spatial modulational instability induced by the dynamical interaction of two strongly coupled fundamental and harmonic fields in a second-order nonlinear optical material is demonstrated experimentally. This phenomenon is explained theoretically on the basis of a one-dimensional Floquet theory. At high intensities, the formation of a 1D solitary wave lattice is superseded by the onset of 2D modulational instabilities. © 1997 The American Physical Society