Optical data transmission over medium distances has so far largely been based on glass fibres. Although polymer optical fibres (POF) have a higher optical attenuation, they are considerably cheaper to manufacture and, due to their design, easier to use. In order to implement an Ethernet connection with a single POF, an optical coupling element is required as part of FlexBiPOF, which couples light signals into the POF and simultaneously transmits signals in the opposite direction of communication to the corresponding receiver. It should be noted that the transmitter and receiver of a communication partner are not directly connected to each other in order to avoid crosstalk. Flexographic printing can be used to produce PCB-integrated fibre optic cables that spatially separate the transmitter and receiver from each other. The waveguide element must have appropriate optical attenuation and coupling efficiencies in the PCB frame to ensure signal fidelity. The complexity arises from the PCB integration process, which influences both optical influences of the waveguides. The project is being carried out at the Institute of Transport and Automation Technology in cooperation with an industrial partner from the PCB sector.