Thin glass based electro-optical circuit board (EOCB): Waveguide process, PCB technology, and coupling interfaces

Optical interconnects for data transmission at board level offer increased energy efficiency, system density, and bandwidth scalability compared to purely copper driven systems. We present recent results on manufacturing of electro-optical printed circuit board (PCB) with integrated planar glass waveguides. The graded index multi-mode waveguides are patterned inside commercially available thin-glass panels by performing a specific ion-exchange process. The glass waveguide panel is embedded within the layer stack-up of a PCB using proven industrial processes. Some of these processes are described in more detail. Furthermore the paper presents the design, manufacture, assembly and characterization of the first electro-optical backplane demonstrator based on integrated planar glass waveguides. Error-free data communication with data rates of up to 32 Gb/s per channel has been demonstrated.