Abstract

In massively parallel computers, electrical networks have the serious problems regarding pin bottle-necks in switches, and the number of pathways between processor elements (PEs). In electrical networks, the number of pins for a chip decides the channel size for electrical crossbar switches, and network size. The number of pins for 16 ch crossbar switches exceeds more than IK (1,024), when the 32 ch external-buses are used. The 16 ch size may be limited in a chip for an electrical switch. By using the 16 ch switches, a maximum 128 ch Clos network[l], with only a strictly non-blocking function, may be accomplished. Photonic technologies may serve larger size crossbar switches, and they achieve more than 1K ch networks. Free-space optics may also overcome pathway problems, because light beams can cross each other with no mutual interference. Various data multiplexing technologies may be used in optical networks.

© 1995 Optical Society of America