The existence and stability of three-wave solitons, both and dimensional, that result from a double-resonance (type I plus type II) parametric interaction in a purely quadratic nonlinear medium are investigated. We demonstrate the existence of a family of stable solitons for a broad parameter range in the double-resonance model. Further, these solitons exhibit multistability, a property that is potentially useful for optical switching applications. We introduce a way to measure the quality of multistability and use this measure to compare the double-resonance model with single-resonance models in media. We also discuss the modulational instability of the double-resonance system and present physical estimates of the power required for soliton generation.
© 2000 Optical Society of America