Electro-optical backplane demonstrator with gradient-index multimode glass waveguides for board-to-board interconnection

First time an electro-optical circuit board (EOCB) is demonstrated with integrated planar glass multimode waveguides and with optical pluggable line card connectors. The waveguides are patterned inside commercially available thin-glass panels by performing a two-step thermal ion-exchange process. The resulting low-loss multimode waveguides possess a gradient-index profile. The glass waveguide panel is embedded within the layer stack-up of a printed circuit board (PCB) using proven industrial processes. Cut-outs inside the PCB are structured for assembling a pluggable optical connector and receptacle system for connecting optical fiber based waveguides on the line cards to integrated optical waveguides in the backplane. The demonstration platform comprises a standardized sub-rack chassis and five pluggable test cards with pluggable optical connectors and designed for housing optical engines. The test cards support a variety of different data interfaces for bidirectional signal integrity measurements. The evaluated demonstrator system performed with bit error free data transmission at 10.3 Gb/s for the tested wavelengths of 850 and 1310 nm.