Electro-optical circuit boards with single- or multi-mode optical interconnects

Embedded optical architectures are required in data center and network systems to replace the electrical signal lines with optical interconnects for increased high-speed data transmission due to the higher bandwidth by length product. MT terminated fiber- or polymer flex parallel optical interconnects seem to be the first step of implementation in commercial applications, without the need to change the printed circuit board (PCB) stack-up design and fabrication process flow and provide standard connector interfaces. However, integration of optical polymer or glass waveguide layers in the PCB stack-up benefits in low-cost high-volume waveguide fabrication with complex layouts including splitters, combiners, crossings, and tight bends. The chapter introduces state-of-the-art electro-optical circuit board fabrication technologies, termination, and performance demonstration for optical waveguides made of polymer and glass.