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Advances in high performance computers and signal processing systems have led to parallel
system architectures. The main limitation in achieving the performance expected of these
parallel systems has been the realization of an efficient means to interconnect many
processors into a effective parallel system. Electronic interconnections have proved
cumbersome, costly and ineffective. The Optical Fiber Crossbar Switch (OFCS) is a compact
low power, multi-gigahertz bandwidth multi-channel switch which can be used in large scale
computer and telecommunication applications. The switch operates in the optical domain
using GaAs semiconductor lasers to transmit wideband multiple channel optical data over
fiber optic cables. Recently, a 32 X 32 crossbar switching system was completed and
demonstrated. Error free performance was obtained at a data bandwidth of 410 MBPS, using
a silicon switch IC. The switch can be completely reconfigured in less than 50 nanoseconds
under computer control. The fully populated OFCS has the capability to handle 12.8 gigabits
per second (GBPS) of data while switching this data over 32 channels without the loss of a
single bit during switching.
GaAs IC technology has now progressed to the point that 16 X 16 GaAs based crossbar
switch Ics are available which have increased the data bandwidth capability to 2.4 GBPS.
The present optical interfaces are integrated GaAs transmitter drivers, GaAs lasers, and
integrated GaAs optical receivers with data bandwidths exceeding 2.4 GBPS. A system using
all Ill-V switching and optoelectronic components is presently under development for both
NASA and DoD programs. The overall system is designed to operate at 1.3 GBPS.
It is expected that these systems will find wide application in high capacity computing
systems based on parallel microprocessor architecture which require high data bandwidth
communication between processors. The OFCS will also have application in commercial
optical telecommunication systems where high bandwidth communication has already
exceeded 2 GBPS. There are also critical requirements for a secure fiber optic switching
system in military Command Control Communication (C3) situations.
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