Pluggable Electro-Optical Circuit Board Interconnect Based on Embedded Graded-Index Planar Glass Waveguides

Abstract

Widespread adoption of electro-optical circuit boards based on embedded glass waveguide technology would enable seamless optical connectivity from external fiber-optic networks to system embedded optical interconnect architectures. In this paper, we report on the fabrication of planar multimode waveguides within thin glass foils based on a two-step thermal ion exchange process. Novel lamination techniques were developed to allow glass waveguide panels to be reliably integrated into a conventional electronic multilayer printed circuit board. In addition, a complete suite of optical connector technologies were developed to enable both direct fiber-to-board and board-to-board connectivity. We present the design, development, and characterization of a fully integrated connection platform, comprising a $281 \times 233$ mm2 multilayer electro-optical backplane with integrated planar glass waveguides, a pluggable connector system, and five pluggable test cards. Both on-card and externally generated 850 and 1310-nm optical test data were conveyed through the connector and waveguide system and characterised for in-system and system-to-system optical connectivity at data rates up to 32 Gb/s per channel exhibiting bit error rates of less than $10^{-12}$ .