Flexo-printed polymer waveguides for integration in electro-optical circuit boards

Electro-optical circuit boards (EOCBs) offer great potential for short-ranged data transmission in highly electro-magnetic inflicted environments. Finding a cost-efficient way to manufacture EOCB only using additive printing processes could establish, increase, and secure data transmission in PCB systems. Flexo printing is an efficient manufacturing process that combines high contour resolution and layout flexibility to create optical waveguides. Previous research has shown that printing waveguides on a polymethylmethacrylate substrate can enable optical data transmission for up to 20 cm. However, a thermo-resistant polyimide (PI) substrate is needed to integrate printed waveguides into PCB. Since PI does not meet optical demands, waveguide cores must be separated by printed optical cladding. This research aims to investigate the additive printing process, which stacks various polymers to achieve waveguides that are ready for integration. Further, the integration in PCB is validated according to functional testing of the optical structures. An entire manufacturing process for printed EOCB is presented, which enables the investigation of optical coupling processes in upcoming research.