Manufacturing Group took a monumental step for the CATV market by adapting the
HLC process to angle polished connectors. Angle polished connectors have been
used for years in high speed video transport applications due to inherent low
reflection characteristics. The fragile nature of fiber mating surfaces,
however, has continued to plague an industry that is more competitive than
With the growing video on demand and streaming video content on the web, a need
arises for high quality fiber optic products capable of withstanding this
trend. Industry leaders and providers are having to transition into a more
competent network infrastructure to conform to the now industry standard of
high performance fiber optic networks.
The SCRATCHGUARD™ Fiber Optic Patch Cords (by Megladon Manufacturing Group) is
a critical step forward in quality. The fiber optic connector is a crucial
component and the “gateway to the fiber optic cabling network”. Damage to the
connector due to repeated use has been the biggest problem for network
managers, until now. The patented SCRATCHGUARD™ Fiber Optic Patch Cords have
virtually eliminated the problem. “We have studied the Megladon Manufacturing
products and spoken with several major network operations that are using these
breakthrough products. The product exceeds anything else they have ever used.”
said Frank Bisbee, Editor of the Heard On The Street column (www.wireville.com). “Jim Hayes, President
of the Fiber Optic Association (www.thefoa.org)
confirmed the need for education in the fiber optic communications industry as
new solutions are coming to the marketplace like a tsunami.” Bisbee added.
Megladon’s SM APC HLC SCRATCHGUARD fiber optic patch cords are ideally equipped
for network installers that are utilizing high speed video networks. The HLC
technology provides mating surface durability and low loss; paired with an
Angle Polish Connector we now have a product that significantly reduces
reflection, cutting down on interruptions in any given network.
“Up until now CATV and high speed video applications have not been able to
take advantage of our HLC patented processes due to standardization on angle
polish connectors. Now they can not only experience the HLC SCRATCHGUARD
durability, but we added a reduction in insertion loss and reflection over
traditional angle polish products,” said John Culbert, President of Megladon.
Megladon® Manufacturing Group Ltd., a subsidiary of TyRex Group Ltd.®, is
recognized as a leader in the fiber optic marketplace. Founded in 1997,
Megladon made it their mission to provide customers with fiber optic products
that far exceed industry standards. As technology innovators, Megladon created the HLC® (Hardened Lens Contact)
termination, which has changed the market and taken it to the next level. For additional information on Megladon and their
patented processes please visit the company’s website at www.megladonmfg.com.
What is Business Critical?
HLC cables are well suited for use in the
harshest environments and the most demanding situations. In testing and manufacturing, HCL patch
cords can withstand constant plugging and unplugging for years without
substantial damage or performance loss. The HLC surface provides minimal
optical signal loss making it the ideal choice for video and cable TV applications. For
the military and other
remote location uses, when replacements are not readily available HCL cables
are far more reliable. In Municipal communications systems involving 911 and emergency communications HLC
cables have dramatically reduced troubleshooting calls. In any business where
the highest performance levels are required Megladon’s HLC, Hardened Lens
Contact fiber optic patch cords are the clear choice.
Scratch Test demonstration video
The Fiber Optic
Association - Tech Topics
OLD STYLE CONNECTORS
In the development
of fiber optic technology over the last 30 years, many companies and
individuals have invented the "better mousetrap" - a fiber optic
connector that was lower loss, lower cost, easier to terminate or solved some
other perceived problem. In all, about 100 fiber optic connectors have been
introduced to the marketplace, but only a few represent the majority of the
market. Here is a rundown of the connectors that have been the leaders of the
Most fiber optic connectors are plugs or so-called male connectors with a
protruding ferrule that holds the fibers and aligns two fibers for mating.
They use a mating adapter to mate the two connectors that fits the securing
mechanism of the connectors (bayonet, screw-on or snap-in.) The ferrule
design is also useful as it can be used to connect directly to active devices
like LEDs, VCSELs and detectors.
The big silver connector at the bottom of the photo at the right is the
Deutsch 1000, what was probably the first commercially successful fiber optic
connector. It was really a "pin vise" holding a stripped fiber. The
nose piece is spring loaded and was pushed back when the connector was
inserted into a mating adapter. The fiber stuck out into a drop of index
matching fluid on a plastic lens. This solution was state of the art in the
late 70s, yielding about 3 dB loss. Many users remember it as the connector
on the front panel of the original Tektronix OTDR.
Above it is the Biconic,
the yellow body indicating a SM version. Developed by a team led by Jack Cook
at Bell Labs in Murray Hill,
NJ, the Biconic was molded from
a glass-filled plastic that was almost as hard as ceramic. It started with
the fiber being molded into the ferrule. This lasted until the company could
get a 125 micron/5mil pin insert into the plastic mold, at which point the
fiber was glued into the ferule with epoxy. When singlemode versions first
appeared, the ferrules were ground to center the fiber core in the ferrule to
reduce loss. Since it was not keyed and could rotate in the mating adapters,
it had an airgap between the ferrules when mated, meaning loss was never less
than 0.3 dB due to fresnel reflection. Usually MM Biconics had losses of
0.5-1 dB and SM 0.7 dB or higher.
The advent of the ceramic
ferrule in the mid-80s in Japan
changed the connector designs forever. The ceramic ferrule was hard and
precise. Fibers were accurately located for alignment and ferrules could be
allowed to touch. Adding in convex ferrules for PC (physical contact) between
connectors reduced losses to levels below 0.3 dB for both MM and SM
In the late 90s, small
form factor (SFF) connectors became popular, but only the LC (top) has been a
runaway success, both in telcos and high bit rate LANs, SANs, etc.
Below are some more of
the popular connectors over the years.
the earliest days of fiber optics, orange, black or gray was multimode and
yellow singlemode. However, the advent of metallic connectors like the FC and
ST made color coding difficult, so colored boots were often used. The TIA 568
color code for connector bodies and/or boots is Beige for multimode
fiber, Blue for singlemode fiber, and Green for APC (angled)
NOTE: THIS MAKES A GOOD STUDY GUIDE FOR THE FOA
CFOT AND CFOS/C EXAMS!
Guide to Fiber Optic Connectors
Check out the "spotters guide" below and you
will see the most common fiber optic connectors. (All the photos are to the
same scale, so you can get an idea of the relative size of these connectors.)
If you wonder what the connector names mean, see Fiber
Optic Connector Terminology in The FOA Online Reference
Guide to Fiber Optics.
top: LC, SC, Biconic, Deutsch 1000
ST (an AT&T
Trademark) is probably still the most popular connector for multimode
networks (ca. 2005), like most buildings and campuses. It has a bayonet mount
and a long cylindrical 2.5 mm ceramic (usually) or polymer ferrule to hold
the fiber. Most ferrules are ceramic, but some are metal or plastic. A mating
adapter is used to mate two connectors (shown below.) And because STs are
spring-loaded, you have to make sure they are seated properly. If you have
high loss, reconnect them to see if it makes a difference.
connectors have the same ferrule size - 2.5 mm or about 0.1 inch - so they
can be mixed and matched to each other using hybrid mating adapters. This
makes it convenient to test, since you can have a set of multimode reference
test cables with ST or SC connectors and adapt to all these connectors. See
SC is a snap-in connector
also with a 2.5 mm ferrule that is widely used for it's excellent
performance. It was the connector standardized in TIA-568-A, but was not
widely used at first because it was twice as expensive as a ST. Now it's only
a bit more expensive and much more common It's a snap-in connector that
latches with a simple push-pull motion. It is also available in a duplex
FC was one of the most
popular singlemode connectors for many years. It also uses a 2.5 mm ferrule,
but some of the early ones use ceramic inside stainless steel ferrules. It
screws on firmly, but you must make sure you have the key aligned in the slot
properly before tightening. It's been mostly replaced by SCs and LCs.
Mating Dissimilar Connectors
The ST, SC and LC connectors share a 2.5 mm ferrule design so they can be
mated to each other. To do so requires a hybrid mating adapter as shown here.
From the top:
LC is a small form factor
connector that uses a 1.25 mm ferrule, half the size of the SC. Otherwise,
it's a standard ceramic ferrule connector, easily terminated with any
adhesive. Good performance, highly favored for singlemode.
The LC, MU and LX-5
use the same ferrule but cross-mating adapters are not easy to find.
FDDI - ESCON
Besides the SC Duplex,
you may occasionally see the FDDI and ESCON* duplex connectors which mate to
their specific networks. They are generally used to connect to the equipment
from a wall outlet, but the rest of the network will have ST or SC
connectors. Since they both use 2.5 mm ferrules, they can be mated to SC or
ST connectors with adapters.
FDDI - above - has a
fixed shroud over the ferrules
ESCON - below - the
shroud over the ferrules is spring-loaded and retracts
*ESCON is an IBM trademark
MT-RJ is a duplex
connector with both fibers in a single polymer ferrule. It uses pins for
alignment and has male and female versions. Multimode only, field terminated
only by prepolished/splice method.
MT-RJ, Volition and
Opti-Jack (below) are difficult connectors to test, as most test sets do not
allow direct adaptation to the connector. If you have to use hybrid (ST or SC
to MT-RJ) reference cables, you cannot do a Method B (one jumper reference)
insertion loss test. Usually the solution is to do a three cable (Method C)
The Panduit Opti-Jack is
a neat, rugged duplex connector cleverly designed aournd two ST-type ferrules
in a package the size of a RJ-45. It has male and female (plug and jack)
3M's Volition is a slick,
inexpensive duplex connector that uses no ferrule at all. It aligns fibers in
a V-groove like a splice. Plug and jack versions, but field terminate jacks
LX-5 is like a LC but
with a shutter over the end of the fiber.
MU looks a miniature SC
with a 1.25 mm ferrule. It's more popular in Japan.
MT is a 12 fiber connector
for ribbon cable. It's main use is for preterminated cable assemblies and
cabling systems. Here is a 12 fiber MT broken out into 12 STs.
This connector is sometimes called a MTP or MPO which are commercial names.
Deutsch 1000 was probably
the first commercially successful fiber optic connector. It was really a
"pin vise" holding a stripped fiber. The nose piece is spring loaded
and was pushed back when the connector was inserted into a mating adapter.
The fiber stuck out into a drop of index matching fluid on a plastic lens.
This solution was state of the art in the late 70s, yielding about 3 dB loss.
Many users remember it as the connector on the front panel of the original
Amphenol developed the
SMA from the "Subminiature A" hence SMA, microwave connector. The
model 905 had a machined ferrule exactly 1/8 inch in diameter that mated in a
machined adapter. When the adapters were not precise enough for better
fibers, a necked-down ferrule that mated with a Delrin adapter for better
insertion loss performance. These connectors are still in use on some
military and industrial systems.
This is the Biconic, the
yellow body indicating a SM version - MMs were usually black. Developed by a
team led by Jack Cook at Bell Labs in Murray
Hill, NJ, the
Biconic was molded from a glass-filled plastic that was almost as hard as
ceramic. It started with the fiber being molded into the ferrule. This lasted
until the company could get a 125 micron/5mil pin insert into the plastic
mold, at which point the fiber was glued into the ferule with epoxy. When
singlemode versions first appeared, the ferrules were ground to center the
fiber core in the ferrule to reduce loss. Since it was not keyed and could
rotate in the mating adapters, it had an airgap between the ferrules when
mated, meaning loss was never less than 0.3 dB due to fresnel reflection.
Usually MM Biconics had losses of 0.5-1 dB and SM 0.7 dB or higher.
Jacj Cook retired from
Bell Labs and started Dorran Photonics which became 3M fiber optics.
The NEC D4 was probably
the first connector to use ceramic or hybrid ceramic/stainless steel
ferrules. It uses a smaller ferrule than SCs or FCs. It was widely used in
telco networks in the 80s to early 90s and some may still be in use.
The AMP optimate was
popular in the early 80s. It used a conical plastic ferrule and screw-on nut.
It was available for every fiber size including plastic fiber. Some may still
be in use in utility and industrial systems.
Also see Fiber
Optic Connector Terminology and The FOA Online Reference
Guide to Fiber Optics.