A wafer scale optical bus interconnection prototype

Prototypes of a wafer wide optical bus interconnection technology are described. By optically coupling subsystems on the wafer, faults normally found in electrically based interconnection topologies are avoided. Wire buses are more prone to errors than waveguides due to the nature of the material involved and requirements for connectivity. This is accomplished through the incorporation of a planar waveguide which couples emitter/detector pairs. This waveguide supports an omnidirectional emission from an optical diode to all receivers on the wafer. The authors emphasize the emitter properties of the light emitting diode (LED) and its coupling to the waveguide. Details of the current prototypes are given along with data on the output of the waveguide. A photograph of the light emitted from the edge of the waveguide along with analysis and waveforms is included. The 5-micron waveguide provided improved coupling and quite flat output along the edge as compared to a 0.3-micron device. Current work utilizes a single wavelength source from a LED transmitting at 1.4 Gbit/second