A glass optical waveguide process has been developed for fabrication of electro-optical circuit boards (EOCB). Very thin glass panels with planar integrated single-mode waveguides can be embedded as a core layer in printed circuit boards for high-speed board-level chip-to-chip and board-to-board optical interconnects over an optical backplane. Such singlemode EOCBs will be needed in upcoming high performance computers and data storage network environments in case single-mode operating silicon photonic ICs generate high-bandwidth signals [1]. The paper will describe some project results of the ongoing PhoxTroT project, in which a development of glass based single-mode on-board and board-to-board interconnection platform is successfully in progress. The optical design comprises a 500 μm thin glass panel (Schott D263Teco) with purely optical layers for single-mode glass waveguides. The board size is accommodated to the mask size limitations of the fabrication (200 mm wafer level process, being later transferred also to larger panel size). Our concept consists of directly assembling of silicon photonic ICs on cut-out areas in glass-based optical waveguide panels. A part of the electrical wiring is patterned by thin film technology directly on the glass wafer surface. A coupling element will be assembled on bottom side of the glass-based waveguide panel for 3D coupling between board-level glass waveguides and chip-level silicon waveguides. The laminate has a defined window for direct glass access for assembling of the photonic integrated circuit chip and optical coupling element. The paper describes the design, fabrication and characterization of glass-based electro-optical circuit board with format of (228 x 305) mm2

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

The ongoing development focuses on low-loss single-mode glass waveguide panel integration in multi-layer electro-optical circuit boards (EOCB) and optical interconnection by micro-optics to the grating couplers of such assembled silicon photonic chips