We predict the existence of optical domain walls and quasi-rectangular localized modes in waveguide arrays with quadratic nonlinearity. An analytical criterion for the stability of these localized modes is derived and confirmed by direct numerical calculations. The instability gain near the respective boundaries is calculated. The instability predicted is controllable by input power and therefore has a potential for use in new all-optical switching schemes. Parameters of the waveguide arrays made from titanium-indiffused lithium niobate as well as the required power levels are estimated.
© 1999 Optical Society of America
(130.4310) Integrated optics : Nonlinear
(190.4390) Nonlinear optics : Nonlinear optics, integrated optics
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.5530) Nonlinear optics : Pulse propagation and temporal solitons
A. Kobyakov, S. Darmanyan, T. Pertsch, and F. Lederer, "Stable discrete domain walls and quasi-rectangular solitons in quadratically nonlinear waveguide arrays," J. Opt. Soc. Am. B 16, 1737-1742 (1999)