Biomedical Engineering Reference
In-Depth Information
fibers while heating and pulling the fiber. When completed, this type of
interconnect is an example of excellent passive interconnect, although the
system gain requirements for the end to end response are prohibitive for LSI
type fanouts utilizing laser diodes.
2.9.2 Fiber-Optic Data Busses
Fiber-optic data buses interconnect a number of spatially separated data
points to permit any one point to communicate with any other point. They
consist of a transmission medium, a mechanism for control of transmission
over the medium, and an interface at each data location to provide a means
for accessing the data bus. Data bus networks have several advantages over
other network topologies such as point-to-point link. Most important, a data
bus can make possible the interconnection of a set of points when the num-
ber of points is so large that interconnection through individual point-to-
point links becomes impractical. Moreover, a data bus topology can provide
considerable configurational flexibility; for example, points can be added to
the network or moved to different locations without major revisions in the
layout. These data buses are constructed using optical fiber and are similar
to the star coupler architecture.
In particular, various data bus configurations can be constructed using
optical fibers and biconical tapered structures connected by fusion splicing.
The maximum number of terminals that can be interconnected for a given
available optical budget between a transmitter and a receiver is dependent on
source power. The connection between points is passive; active components
such as light sources and detectors are located only at the fiber interfaces, so
the failure of an active component at a fiber interface does not prevent the
other points from using the data bus.
2.10 InterconnectRiskAssessments
Interconnect components or combinations of components present risks
dependent on the ultimate data rate and bit error rate (BER) required in
each application. The risks involved in implementing any technology in its
infancy are always great, although certain interconnect methodologies and
hardware carry greater risk than others due to implementation difficulties
with respect to alignment tolerances, power consumption, BER, bandwidth,
and other parameter inadequacies with respect to specific application archi-
tectures. This section endeavors to point out the architectures and hardware
believed to best meet the present and future needs of optical interconnects.
Figure 2.32 illustrates hardware risk assessments and their probability
of being utilized successfully in an LSI application optical interconnect.
Figure 2.33 illustrates architecture risk assessments. Several things should
 
Search WWH ::




Custom Search