New options for chip-to-chip photonic packaging by using thin glass based waveguide substrates on board and module level

Electrical-optical integration is a rapidly growing field with a strong potential for applications in a wide spectrum covering optical sensors, data & telecom, respectively. The driving forces are bandwidth demand, power efficiency and increased channel density. For higher degrees of integration thin glass substrates provide very suitable properties. The technology of the "glassPack" concept relies on the realization of the passive single mode and multi mode optical waveguides within the thin glass substrates and benefits of the excellent optical, electrical, and thermal properties of glass itself. Suitable technologies are ion-exchange and direct optical butt coupling by laser fusion. The planar integrated single- or multi-mode waveguide is characterized by a graded refractive index profile. The laser fused fiber interconnect shows a determinate coupling loss. Also, planar waveguide array coupling elements of very flexible design can be applied for optical coupling and 90 degree light deflection. Novel innovative features are added to this packaging technique to leverage its generic usage. For electrical wiring thin film technologies and through glass vias have been demonstrated to address high integrate photonic System-in-packaging solutions. All together makes glass to the perfect platform for optical as well as electrical interconnects on board and module level. Multi-mode interconnects in thin glass layers of an EOCB as well as a glass based transceiver module show the integration potential of that approach. The demonstrated development goes hand in hand with ongoing trends in the area of silicon photonics to provide a suitable packaging and interconnection platform. Also the gap between single mode fiber interconnects and single mode SoI (silicon-on-insulator) waveguides in ICs (integrated circuit) can be bridged by the glass based interconnects on board and module level. The paper presents the glass packaging state-of-the art