Abstract: In accordance with the invention, a plurality of glass waveguides (GWL1 . . . GWL4) are arranged in a first plane. In an overlying plane there is arranged at least one polymer waveguide (PWLA) which forms an acute angle with the glass waveguides. Vertical coupling regions are formed where the polymer waveguide intersects the underlying glass waveguides. The coupling properties can be selectively influenced with the aid of heating electrodes (EA1 . . . EA4; EB1 . . . EB4). To switch over light from one glass waveguide into another, the temperature of the vertical coupling regions is set such that light is coupled up from the one glass waveguide into the polymer waveguide, is guided therein, and is coupled down into the desired glass waveguide in another coupling region.

Abstract: In an integrated structure of a beam spread transformer with several buffer layers separated from each other by light guiding layers there is provided on the upper buffer layer an unclad rib waveguide with a tapered section. Between the fiber-facing interface and the tapered section there is provided a section over which the rib is extending. There, the waveguiding layer is completely removed and the exposed buffer layer is reduced symmetrically to a width which is greater than the width of the rib. By the additional rib thus formed coupling independent of polarization is made possible. The coupling is optimized by increasing layer thicknesses of the buffer layers.