OPTOELECTRONIC PARALLEL-PROCESSING WITH SURFACE-EMITTING LASERS AND FREE-SPACE INTERCONNECTS

Parallel optoelectronic processing that uses smart pixel arrays and fr ee space interconnections may provide an attractive alternative to app lications that exhibit a large degree of functional parallelism and re quire massive input/output data rates. Two fine-grain parallel archite ctures based on two-dimensional arrays of processing elements are disc ussed in this paper. The logic complexity of the smart pixels ranges f rom two-input AND and XOR gates for a database filter to multiple-inpu t multiple-output compare-and-exchange modules for a recirculating bit onic sorting unit. Both systems use vertical-cavity surface-emitting l asers as light sources but light detection and logic are implemented d ifferently. The data filter uses GaAs-based phototransistors while the sorting unit requires silicon detectors and CMOS circuitry for its mo re complex logic. The free-space one-to-one interconnection patterns r equired between processing planes can be realized with either refracti ve or diffractive optics and their simplicity and regularity permit ea sy scale-up.