Fiber-optic connectors are more capable, less expensive
As connector performance nears its limit for now, the market turns to price and
ease of use
BY DENNIS HESS
AMP Inc.
Optical Interconnection Systems Group
Harrisburg, PA
The U.S. fiber-optic connector market is cyclical. Advances in new designs and
standards are followed by falling prices. Ten years ago the industry goal was
simply to create a fiber-optic connector that worked well. Soon after, the goal
was better performance, higher reliability, and easier application. The issue
then became price, only later to return to improving performance.
Currently, connector performance is probably near its limit, and the cycle has
moved once again to issues of price and ease of use. The quest for
easier-to-use, reliable connectors has resulted in fast-mount designs such as
epoxyless connectors. These connectors (see Fig.1) eliminate the need for epoxy
and epoxy applicators as well as epoxy-curing equipment like ovens or
ultraviolet light generators. Epoxyless connectors ease installation at job
sites by eliminating the need for immediate electrical supplies, curing ovens,
and outgassing venting. Installers can thus terminate many connectors quickly
with little training involved. Using these connectors allows work to be done in
an occupied building without inconveniencing tenants. Epoxyless connectors
reduce assembly time from 15 min to 2 min, significantly reducing cable
installation costs (see Fig. 2).
Epoxyless connectors are available with ceramic, stainless steel, and polymer
(plastic) ferrules for single-mode and multimode use. These connectors have
proven to be as reliable and to perform equally well as epoxy-type products.
Declining prices
Prices of fiber-optic connectors continue to decline through a combination of
increased competition and volume production by suppliers. During the past two
years, prices of some connectors, such as the ST style, have fallen an average
of 50%. Overall, connector prices have declined 10% during the past year.
Changes in connector materials have also helped to reduce prices. Of the four
main components of a fiber-optic connector (ferrule, coupling device, cable or
fiber support, and housing), the ferrule represents by far the largest portion
of the connector's cost.
Ceramic ferrule costs have traditionally kept connector prices on the high
side. New methods for fabricating and machining are working to lower the costs
of ceramics. Also, manufacturers have developed polymer molding techniques that
produce ferrules equal to or better than ceramic ones. Machining capabilities
for stainless steel ferrules have also improved, and those parts now also
provide high performance at a lower cost. Also, stainless steel improves
ruggedness and durability. The willingness of users to accept nonceramic
materials has been instrumental in the substantial price decline of connectors.
Prices of fiber-optic connectors will continue to fall in 1994, but not as
rapidly as in the past few years. Prices could even stabilize or level off
sometime in the next year. The reason is obvious: if the industry starts out
with a $12 ST-style connector and the price is now $3, there is little room
left for prices to fall. Cost reductions due to volume increases have already
taken place, so efforts will now be directed toward making fiber connectors
easier to use.
Standards mean stability
The early fiber connector marketplace consisted of many proprietary connector
types. Nearly every manufacturer had its own style of connector and design,
which resulted in substantial user confusion. Industry standards groups have
helped to improve this situation dramatically.
Today, most fiber connectors are available from many manufacturers, and
standards exist for particular connectors in specific applications. Examples
include the Fiber Distributed Data Interface (FDDI), Fiber Channel,
Asynchronous Transfer Mode (ATM) and EIA/TIA 568 applications.
Currently, ST-style, FDDI, and SC connectors dominate in networking and
premises applications. In telephone systems, the common connector types are the
FC, SC, and ST-style. The biconic and D4 types are also used in these
applications.
The internal configurations and performance of many of these connectors are
similar, though coupling mechanism and size are often different. The ST
connector, for example, has a bayonet coupling action, while the SC connector
has a push-pull mechanism. The SC connector is considered to be more
user-friendly.
The SC connector (see Fig. 3) also permits higher densities and more flexible
duplex styles, something users want in network implementations. Also, in a
patch panel, installers need enough space between connectors to grip the
connector with their fingers. The SC connector can provide this feature.
Increasing industry acceptance of the SC connector means that connector will
continue to make inroads into the ST-style connector market, though a major
switchover is not expected to happen for some time. The ST connector has a
large installed base and a great deal of familiarity with users. It is now also
lower in price than other connectors because of higher-volume production. The
switch to the SC connector will be driven by users' eventual insistence that
their fiber networks be built entirely according to industry standards.
Fiber-optic connector standards should make users more willing to install fiber
without the fear of locking into an orphan connector type. Standards will also
help to lower costs because of increased volumes of fewer product types. The
accompanying table lists data for popular styles of fiber-optic connectors.
Redefining connectors
In the next few years, fiber-optic connectors will continue to evolve and
employ new technologies. Until now, connectors have been for the most part one-
or two-position with an emphasis on performance, cost, and ease of
application. Now the industry will produce custom designs such as
multiple-position and high-density connectors, paralleling the trend in
electrical connectors seen over the years.
Like electrical connectors, fiber-optic connectors are gradually evolving
toward more specialized designs and applications. Fiber-optic backplane
connectors are increasingly being used, and other multiple-position connectors
will be developed.
New technologies will also be incorporated into future fiber connectors.
Holograms, lensed elements, active components, and integrated devices may be
incorporated to increase performance, reduce size and improve
manufacturability. One fiber connector concept would locate multiple fiber
interconnections, transmitters, and detectors on 0.050-in. centerlines. All of
these developments will further increase the use of fiber-optic data
transmission in all types of applications.
CAPTIONS:
Opening shot:
Fiber-optic connectors have benefited from technology improvements, greater
standardization, and more recently, falling prices.
Fig. 1. A no-epoxy connector, shown here before and after crimping action,
speeds termination for many installers.
Fig. 2. Installed cost for an epoxyless crimp connector is less than that for a
standard epoxy connector.
Fig. 3. The industry is moving toward the SC connector, which permits the
higher densities and more flexible duplex styles that users want in networks.
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