Coupling management of fs laser written waveguides

The evanescent coupling of femtosecond laser written waveguides with elliptical and circular shape is investigated in detail. Elliptical waveguides are used to investigate directional tuning of the coupling properties in a square array by tilting the elliptical waveguides. This allows to specifically pronounce diagonal coupling. In contrast, directional insensitive coupling is demonstrated in a circular waveguide array based on circular waveguides.