Highly efficient waveguide-detector coupling structures for integrated opto-electronical circuits on silicon

The direct waveguide-detector coupling is a highly efficient way to transform optical power guided in an integrated optical waveguide into electrical signals. This paper presents the design, technical realization, measuring setups, and results for waveguide endfire coupling structures to vertical and horizontal diodes on a silicon substrate. The decisive components of the coupling structures such as the step in the substrate, the antireflective coating, the integrated optical striploaded waveguide and different types of PIN-diodes will be discussed. The applications for such structures are demonstrated on an integrated optical pressure sensor and a fast optical detector for wavelength up to 1.1 μm