Nonlinear discrete systems have recently attracted a lot of interest,
due to their generality and appearance in a wide variety of areas. Many
systems in nature and on a variety of scales share the same dynamical
nonlinear properties, and can support stable energy localizations.
These localizations, named discrete solitons, can interact with each
other or with the structure in which they propagate, leading to a
variety of useful applications. A particular class of optical discrete
solitons, propagating in arrays of nonlinear waveguides, has proved to
be a convenient system for the experimental study of nonlinear discrete
phenomena. In addition, their fast response and mutual interactions could be exploited for all-optical switching applications. In this talk, we will discuss the fundamental properties of discrete solitons and will show several experimental applications of nonlinear waveguide arrays to ultrafast all-optical switching.