Electro-optical circuit board with single-mode glass waveguide optical interconnects

Abstract

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

InP-Based Foundry PICs for Optical Interconnects

“…All these parameters are very much inter-related to each other by the way that the light is coupled from the InP PIC to the other PIC (here to be named, the interconnect PIC). Figure 7 shows four of the most common hybrid-integration approaches that are reported in the literature for datacenter-and optical-interconnect applications, which we have subdivided in two types: edge coupling, and surface coupling [20][21][22][23][24][25][26][27][28][29][30][31]. We have been developing three strategies to modify our generic-foundry-service process to enable efficient coupling of light in-and out of the InP PIC for these four hybrid-integration approaches.…”