Localisation effects in waveguide arrays-from Bloch oscillations to discrete solitons

Summary form only given. The primary aim of this contribution is to disclose the peculiarities of light propagation in waveguide arrays. Thus we show that coupling may be considered as discrete diffraction, how it, can be arrested by a linear refractive index variation and how discrete solitons may form as a result of the mutual interplay of this controllable kind of diffraction with nonlinearly induced phase modulation. Potential applications, such as discrete steering and switching as a consequence of both competition between soliton motion and self-trapping, and various destabilisation scenarios are also reviewed.