New generation interconnection technology: printed circuit boards with integrated optical layers

The need for high data rate interconnects within computing and telecommunication equipment is continuously rising. As the performance of electrical interconnects is physically limited through the skin effect, optical interconnects can be used to overcome this problem. Within this paper some results achieved in the frame of the German research and development project NeGIT (new generation interconnection technology), focusing on printed circuit boards with integrated optical waveguides are introduced. The waveguides are part of an optical layer which is manufactured by a photolithographic process. Using standard lamination processes the optical layer is combined with electrical FR4-layers and the result is an electrical-optical printed circuit board which shows a sufficiently high thermal resistivity taking into account the manufacturing processes like lamination and soldering. The compound strength as well as the stability of the optical layer properties are good. Apart from the waveguide technology the concept for optical module-to-board coupling is presented.