Comparison of Waveguided and Free Space Optical Interconnect for Image Processing Applications

To determine the relative efficiencies of different interconnection technologies, we will compare optical interconnects using integrated optical waveguides and free-space with electronic interconnects, noting that the fabrication technology for waveguides and diffractive optical elements (used in free-space optical interconnects) are compatible with electronic manufacturing technology. Integrated optical waveguides are attractive because of higher bandwidth than electronic interconnects. Free-space interconnects appear to be even more attractive because the achievable connectivity is higher than waveguide interconnects. Free-space interconnects are especially suitable for global interconnection, since long distance connections are carried out optically in three dimensions, requiring less area. Using wavelength or orthogonal phase code multiplexing techniques, it will also be easier to reconfigure free-space interconnects for better fault tolerance. We propose to compare quantitatively optical interconnects using waveguides and free-space with electronic interconnects. We will determine the better interconnect technology between free-space and integrated optics. As an option to Phase I, we will produce a few key elements of the better technology. For Phase II, we will produce an optimized interconnect design and a scalable demonstration based on the proposed technology determined in Phase I. The demonstration will be a packaged, optically interconnected multichip module.