Two-dimensional soliton in cubic fs laser written waveguide arrays in fused silica.

The observation of a two-dimensional discrete soliton in a cubic 5 x 5 fs laser written waveguide array in fused silica is reported for the first time. In addition to the localization the sharp edges of the array allow to study the influence of the array's boundaries. The results are in excellent agreement with theoretical predictions and provide the basis for a variety of future applications for nonlinear two-dimensional integrated optical devices.