Interactions of discrete solitons with defects and interfaces

Summary form only given. In this work we study experimentally the interaction of discrete solitons with structural defects in arrays of AlGaAs waveguides. We fabricated both attractive and repulsive defects in otherwise uniform arrays. When a beam is injected in proximity of a defect, little difference is observed between attractive and repulsive defects, as they reflect and transmit the beam accordingly to its transverse velocity. However, when the beam is injected at the defect, trapping takes place in the attractive defect, while the repulsive defect is very unstable and drives the soliton away. We will present a series of different experimental situations, supported by the correspondent numerical analysis.