Quasi-rectangular solitons in quadratically nonlinear waveguide arrays

Summary form only given. Nonlinear optical waveguide arrays on AlGaAs basis have been recently fabricated and localized modes or discrete solitons (DS) have been experimentally identified in this cubic nonlinear environment. Various proposals to exploit such discrete solitons (DS)s in all-optical schemes have been put forward. It is commonly believed, however, that the quadratic nonlinearity may act more efficiently as far as photonics applications are concerned. Moreover, well established fabrication technologies for LiNbO/sub 3/, waveguide configurations´ feed the anticipation that the implementation of quadratic nonlinear arrays is feasible. One potential switching strategy relies on the controlled exploitation of DS instability. However, strongly localized modes occurred to be either always (un)stable or transforming into long-living oscillatory states. In this contribution we aim to demonstrate a novel type of quadratic DSs that possess peculiar stability properties and thus a higher potential for applications.