Computer systems employing reconfigurable board-to-board free-space optical interconnections: COSINE-1 and -2

Parallel-processing computer systems using reconfigurable board-to-board free-space optical interconnections, called COSINE-1 and -2, are presented. In COSINE-1, 36 transputer-accommodated boards are connected by optical links comprised of collimated optical beams and optical fibers. The 144×144 crossbar interconnections are manually rearranged by operating beam couplers which couple the fiber ends to the optical beams. The system was tested for a computer graphic machine, and no degradation of performance was observed in spite of mechanical tremors. COSINE-2 uses an optical Benes switch which can electrically control the interconnection network topology. Since the interconnection state is electrically changed during the system operation, the processor can be used more efficiently. A 16-channel prototype optical switch was constructed and tested