Novel Array Waveguide Evanescent Coupler for Card-to-Backplane Optical Interconnect Applications

Card-to-backplane optical interconnects are required for high-speed opto-electronic packaged computing systems for military target identification, missile interception, and fast access to intelligent database. Present method of waveguide interconnection employs 90° out of plane turn using 45° etched waveguide mirror. Such approach greatly increases cost of manufacture and degrades backplane reliability. Furthermore, the presence of such local waveguide termination consumes optical power even when the card is not plugged in at the interconnect location. New Span Opto-Technology Inc. proposes an array waveguide evanescent coupler for card-to-backplane optical interconnection. Feasibility demonstrated in Phase I, the new coupler facilitates easy coupling between card and backplane waveguides through the use of an auto-alignment coupler hardware. It eliminates the problems of 90° out of plane turn and local waveguide termination. Without card plug-in there is no optical energy consumption at the connector location. With card plugged-in the card-to-backplane coupling efficiency can be adjusted. The maturization of the coupler ribbon and coupler hardware at low cost in Phase II will be a milestone development to near-term commercial implementation of high-speed optical data bus. High-speed optical bus lines will be demonstrated in Phase II along with the exploration of a high-density stacked multi-board vertical optical interconnect system.