New Fiber Friend

Usage of fiber cables by enterprises have been increasing as there has been
an upsurge in the bandwidth demand owing to the steady increase of data
intensive applications and VoIP over the enterprise networks. However,
conventional fiber is considered vulnerable for bending as there are inherent
losses when we tend to bend these fibers during the deployment. This has
resulted in fear psychosis among cabling integrators that deploying fiber cable
is difficult compared to copper cables. This is one of the main reasons that it
did not have a great uptake in the Indian market, though the story is quite
opposite in the developed countries. Now, the question is that which innovation
can make deploying fiber easy for enterprises? The solution lies in making fiber
'bend insensitive', so that the fiber will not be broken easily during the
deployment. Bend insensitive fiber is more appropriately called 'less bend
sensitive fiber', or 'bend resistant fiber', or 'bend optimized fiber', or 'bend
improved fiber' to reflect the true nature of the technology.

Performance Companion

With the FTTx network rollouts proceeding across the world, the fiber to be
installed is subject to a greater degree of bending, since smaller distribution
cabinets and compact fiber management systems are deployed. ITU-T G 6567A offers
an excellent macro bending performance. The bending limits of industry standard
G.652.D fiber has been defined for 60 mm diameter, while the limits for G.657A
has been defined for 20 mm and 30 mm diameters.

The essential difference between conventional fiber and bend intensive fiber
is the allowable bending radia. While the conventional fiber starts
deteriorating the transmission quality at radius 35 mm, the bend insensitive
fibers have two classes-15 mm and 7 mm. Conventional fiber cables require a
certain bend radius to be maintained while laying or using the fiber, and is
kept as straight as possible. Most high-performance optical cables use a form of
armor that resists tight bending. Any tighter coils or bends seriously affect
the data transmission, thus affecting performance. On the other hand, it is
required to lay and use the fiber in geometries, so the bend radius restriction
becomes extremely limiting. Bend insensitive fibers can be used for sharp or
tight bends, and this can be handled and laid far more easily. Bend insensitive
fibers improve system margins in high speed enterprise networks.

What really happens is that bend insensitive multi-mode fibers minimize the
bend-induced attenuation, thereby increasing the system reliability and
decreasing the downtime. Less attenuation means that information transfer is
more reliable. These cables also ensure that there is no chance of dealing with
unplanned attenuation brought about by tighter-than-expected cable bends. New
bend insensitive multi-mode fibers are able to deliver superior bandwidth
performance in an ultra-bendable package without requiring any adjustments to
standard field installation, termination monitoring, or maintenance procedures.

The Next Step

Every structured cabling vendor is making innovative efforts to make the
fiber medium more adoptable for the benefit of enterprises. As a next step in
Tyco Electronics' FTTH system solution, they have developed the wiring of
multi-dwelling units (MDUs) with a mini break out riser cable, which is used
inside the building from the outside plant cable termination to the customer's
interface. These features are very compact to fit into small conduits and
building floor access points, and are extremely flexible small diameter cables
in combination with miniaturized cable accessories. It helps reduce the need for
on-site pre-audits, and the horizontal drop cables can be pulled through the
existing ducts due to their reinforcement. A reduced amount of connectivity
points (splices, connectors) shorten the installation time, and the time spent
inside the customer's premise is minimized in this advanced solution. It is
optimized for brownfield construction networks.

Major industry players like DIGILINK are overhauling its offerings, and in
days to come enterprises would get bend insensitive fibers as default. Other
innovation required is to make the fibers less vulnerable to micro-bends by
devising superior coating techniques. Improved dispersion by designing the
preforms and pulse spreading performance are just a few to name on the
innovations front. DIGILINK is the privileged partner to use the latest, being a
preferred customer of Corning USA, pioneer in fiber technologies today. And,
field crimping type fiber connectors (SM and MM) have been introduced in fiber
components, which don't require epoxy. It takes lesser time to crimp the fiber
connectors, and ensures low insertion losses.

Market Adaptability

According to industry sources, the bend improved G.657.A fiber has high
market adaptability in India. This is set to increase in the coming years as
bandwith requirements would drive FTTx to be a standard feature in India. The
fibers are meant for datacom or LAN/ WAN applications, and this is a solution
meant for our market. Hence, it is bound to become successful in the Indian
market.

Bend improved G.657.A fiber is compatible with G.652.D fiber. The BI fiber
offers a better macro bending loss, providing designer or installer with much
more flexibility. People using fiber or installers laying it will be able to
appreciate the advantages of bend insensitive fiber. Without doubt, freedom from
the restrictions imposed by bend radia are highly desirable, and there is
already an established case for this. Like any other new technology, price does
play a critical role.

The only disadvantage with the fiber is the cost factor, which also would
budge down as the demand increases. As bend insensitive fiber becomes
increasingly competitive with respect to the present day fiber solutions, we
will see a natural shift to this type of fiber as the medium of choice.
Technology conscious customers would be very keen to see this happen very soon.
Though the high cost is a deterrent at present, bend insensitive fiber's primary
advantage of being less sensitive to micro bends and the resultant protection
from transmission losses will drive the market. This cable can be installed even
by unskilled installers.

The Driver

In the recent past, broadband upsurge in developing countries particularly
in 'BRIC'-Brazil, Russia, India, China-there is a huge demand for a higher
bandwith, especially in access networks. So FTTx (fiber to the home/business) is
the primary driver in the enterprises to adopt this solution increasingly.
However, adaptability will be there even in the LAN backbone segment for sure.
There are three obvious choices for the technologies-XDSL, Wi-Fi/WiMax and FTTX.
As enterprises inch towards the need for 1Gbs signal to an individual
subscriber, whether at home (FTTH), or at the office desk (FTTD), or at the curb
in your apartment (FTTC), there is no alternate to a passive optic network,
leading to an extensive use of the fiber medium in the neighborhood.

The applications will be strong across all enterprise verticals. Since the
advent of glass fiber as a communication medium from the early seventies, it has
been preached and practiced that fibers are vulnerable to mechanical stress
especially the bending stress. The fiber cable designs, essentially revolved
around the philosophies to protect fibers from these stress. So FTTx segment
will be the primary driver for this solution.

Basically, greater network reliability and less downtime, future proofed
systems, easier installation across difficult geometries such as 90 degree
bends, reduced time and cost for network installation with lesser bend radius
precautions to be considered, and reduced operating costs of bend improved fiber
solution would encourage enterprises to adopt this solution.

Bend insensitive fiber cable has generated quite a buzz in the market. It is
a great step forward in optical fiber construction as it makes multi-fiber
assemblies less susceptible to macro bends that affect the attenuation and limit
the bandwidth of optical fiber links.

However, for enterprises of any size, it is crucial for the health and
performance of their network to understand that the reduced bend radius fiber
does not, in any case, mean that the fundamentals of proper fiber management are
to be ignored. In fact, as bend improved fiber is deployed for any network using
data intensive applications, factors such as connector access and cable routing
paths become even more crucial. Last but not the least, deploying bend
insensitive fiber is just one aspect of a complete strategy for an efficient,
future proof network management across any enterprise.

Kannan K

kannan@cybermedia.co.in