Thin glass based electro-optical circuit board (EOCB) with through glass vias, gradient-index multimode optical waveguides and collimated beam mid-board coupling interfaces

First time an electro-optical circuit board (EOCB) is demonstrated with integrated planar multimode glass waveguide panel and out-of plane spherical mirror based coupling elements. Such EOCBs will be needed in upcoming high performance computers and data storage network environments. Light from 850 nm up to 1550 nm can be directly coupled from the optical engine mounted mid-plane on the EOCB and coupled into low loss optical waveguides for signal transmission. The demonstration platform comprises a multilayer EOCB with 1301 electrical through glass vias (TGVs), two embedded thin glass layers, planar integrated gradient-index multimode glass waveguides and mid-board optical coupling interface. The evaluated demonstrator system performed with insertion loss of 1.94 dB at wavelength of 850 nm for link distance of 7.1 cm. In best case without misalignment the out-of plane coupling loss is 3.5 dB.