The amount of data to be transmitted is increasing in all technical areas, so that optical transmission lines are also becoming more and more interesting on three-dimensional Mechatronic Integrated Devices (3D-MID). An innovative manufacturing approach for optical waveguides is the additive manufacturing using the mosquito method. In this process a liquid polymer, which serves as the cladding material of the waveguide, is applied into a cavity. A micro dispensing needle is then stitched into the liquid cladding. The material for the waveguide core is dispensed into the cladding and the waveguide is realized by a relative movement of the dispensing needle and the substrate. Finally, the entire structure is cured with UV radiation. This method allows it to create waveguides with different core diameters down to single-mode waveguides. The printed waveguides are characterized regarding dimension and optical transmission behavior.