May/June 2019 I 51
FIGURE 7: When the splice is completed, the fusion splicer then displays
the splice loss estimates.
TESTING THE SPLICE
Once the splice is complete, the
fusion splicer displays the resulting
splice loss estimates as shown
in Figure 7.
It is important to remember that
the displayed splice loss is only
an estimate and should be validated
with an optical time domain
reflectometer (OTDR) or a laser
source/optical power meter (OPM).
The estimated loss is based on the
cleave quality, the axial alignment,
and the shape of the burn area.
Some customers require OTDR
documentation, submitted as
a “birth certificate,” to prove that
the fiber link meets specification.
The certificate is then retained
on file, also providing the
documentation required for
successful subsequent troubleshooting
and data center
rework/expansion.
CONNECTIVITY
CONSIDERATIONS
Preterminated Cables
When the length of many cables
between switches and servers
is the same, preterminated cables
can be a viable method of
connection. One of the
disadvantages of preterminated
cables is that the data center does
not have much room for slack
storage. As a result, the cables need
to be the correct length for the run
with only perhaps a six foot
overage per end to accommodate
the cable having to be moved
to a different location within the
rack. If the correct length of cable
is available or if a large number
of custom cables can be ordered,
then true plug-and-play
connectivity is a very viable
option over fusion splicing. Using
preterminated cables can eliminate
or reduce the need for large CAPEX
spending, which allows the
installation contractor to use
a less skilled workforce.
Another advantage of
preterminated cables is that they
are factory manufactured under
controlled conditions that lends
itself to a potentially high-quality
connection that is guaranteed
to meet specifications.
Splice-on-Connectors
Just as with single fiber optic cables,
a splice-on-connector (SOC)
provides a convenient method
to terminate a ribbon cable. An
SOC provides a factory polished
connector interface with a factory
cleave of the ribbon. SOCs also
eliminate the need for adhesives
or crimping procedures. With the
optical fiber being fully prepared,
the most difficult and timeconsuming
process of fiber
preparation is completed for the
technician. The splice protector
is housed inside of the SOC, which
eliminates the need for a splice
tray and eases the installation
process. The resulting fusion
splice generally has very low loss
and low reflectance that is needed
for successful high-speed
data transmission.