Fiber optic waveguide arrays as an artificial medium for discrete optics

Weakly coupled waveguide arrays are a new artificial optical medium. It differs from bulk media by the discrete spatial structure along the transversal dimensions of light propagation. Therefore, a distinct feature of this medium is the discrete diffraction which is of diffusive or coherent type in random or periodic arrays, respectively. Substantial progress has been made in the theory (discrete optics) and experimental evidence was given mainly using one-dimensional (1D) arrays. In 2D-arrays spatio-temporal light structures (light-bullets) are predicted that cannot be observed in bulk media. To study the phenomena experimentally and to assess its relevance for optics, media are needed which meet the experimental requirements. Hexagonal multi-core silica array fibers are promising model systems for this purpose. We discusse such arrays with respect to the preparation, characterisation and linear optical effects including boundary effects. Using a high precision fiber technology, a low coherent discrete diffraction was achieved. With this technology different 1D- and 2D-array structures were fabricated and investigated, which are the basis of future experiments on light-bullets.