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Problem Solved: Fiber Optic Interconnect Solutions
By Jerome Farnan, Director of Fiber Optic Technology, Winchester
Electronics
When the facility
architects at a major broadcaster started thinking about an all-optical
fiber network fabric in 2007, many pieces of the puzzle were still
missing. Many router manufacturers did not yet offer optical fiber
inputs or outputs, optical-to-electrical and electrical-to-optical
converters were expensive, and generally, optical fiber seemed difficult
to work with. The rule of thumb was to use fiber only where you had
to—for long cable runs or signals 3Gb/s and above.
Other problems came up during the handling of fiber. If you treated it
like coax, it just didn’t seem to work. With most technicians and
installers inexperienced with maintaining fiber networks, a simple
reconfiguration could turn into a nightmare if a connector became dirty
or scratched, resulting in a lost signal with no easy way of restoring
it. There was no way to patch fiber without physically disconnecting the
equipment side of the installed equipment.
Around this same time, Winchester Electronics engineers met with this
broadcast facility’s systems engineering team, and they listened to the
issues experienced with fiber optics and the description of the missing
link—a rugged fiber optic video patching system. This meeting, almost
two years ago, was just an exchange of ideas, but it seemed clear that
the combined expertise of Winchester’s recent acquisitions, Advanced
Interconnect and Kings Electronics, could provide a solution.
 Fast
forward to 2009. Today, all matrix router manufacturers offer fiber
inputs and outputs, fiber HD cameras are proliferating, there’s heavy
demand for 3GB/s studio infrastructure, and Winchester’s KINGS®
brand EL-Series™ fiber optic video jack and patching system,
including rugged, no-clean expanded light beam fiber optic connectors,
is transforming the fiber experience for numerous companies around the
world.
Despite its idiosyncrasies, the cost advantages of fiber outweigh the
benefits of familiarity associated with traditional copper
methodologies. The broadcast facility’s lead system engineer summarized
some of the advantages. “If we use an all-fiber distribution
infrastructure, we can realize some amazing savings; in long runs and
central distribution, you can eliminate DAs (distribution amplifiers),
which not only incur costs for the initial purchase, but also for
maintenance, power, cooling, and use of floor space to rack up.”
He went on to describe other advantages of optical fiber over copper.
“Fiber is much higher density cabling, so under-floor cabling systems,
such as cable trays, can be dramatically down-sized or eliminated,” he
said. “In new facilities, less under-floor space can save on building
construction costs.”
Additionally, fiber can carry many different kinds of signals,
eliminating the need for multiple cabling formats and connector types.
“This also lends itself to not having abandoned under-floor cable, since
it can be reused for a different signal format than the original
installation. CAT3 cable will only ever be CAT3 cable. You can't run
high bandwidth over it, nor can you practically use it for video or
audio,” he said.
“If (when) signal formats change, such as a dramatic increase in signal
bandwidth, fiber can easily carry signals into the tens or hundreds of
gigabits. Currently, cabling would have to be duplicated and then older
cabling removed after the changeover. Removal of obsolete cabling can be
expensive and dangerous in an on-air facility.
“The passive nature of an all-optical infrastructure can also lower cost
of maintenance. With no active devices in the signal distribution path,
failures can be eliminated. Simple test equipment can test virtually all
fiber paths.”
 Winchester’s
KINGS brand EL-Series (to denote Expanded Light) connector system uses a
patent-pending optical alignment that is different from any existing
high-cost, high-loss expanded light beam system, and very different from
the traditional ferrule-based fiber, which is so prone to scratches and
dirt.
Expanded beam is a proven technology that has been used in military and
high-reliability connectors for some time, but in general, its cost and
size made it prohibitive for use in mainstream implementation. It works
by focusing the light exiting from an optical fiber into a beam with a
cross-sectional area hundreds or thousands of times the size of a
ferrule-based fiber connector. This means that dirt and dust have little
or no measurable impact on the optical throughput, and, as they are
non-contact, there is no wear or scratching. The 2009 IABM award-winning
EL-Series uses a patent-pending optical-to-mechanical
alignment technique, miniaturizing the optical contact, lowering costs,
simplifying alignment, and allowing its use with single-mode fiber,
while maintaining a very low back-reflection and low insertion losses.
The video jack is a full-normal optical fiber video jack, or more
generically, a mechanically actuated 2x2 single-mode optical switch. By
implementing expanded light beam connectors front and rear, the video
jack is made simple, fully passive, and small enough to fit 32 video
jacks across a 19-inch rack. The patch-side connectors are push/pull
connectors with a three-pound insertion force and six-pound extraction,
enough to prevent it from being inadvertently pulled out as you walk
past the rack, yet allowing fast reconfiguration without having to
fiddle with latches, tools, or twisting. On the equipment side, the
latching method is borrowed from the DIN 1.0/2.3 mechanical interface,
providing a latching connection with a more than 20-pound retention, but
allowing extraction by using DIN extraction tools, or by hand.
By implementing exactly the same look and feel as the copper jackfield,
and providing a rugged no-clean fiber optic connector, the transition to
an all-optical fiber studio infrastructure is straightforward and highly
attractive.
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