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Fiber Optic Services And Products
EYE ON FIBER
NINE ADVANTAGES OF FIBER OPTIC
COMMUNICATIONS
Executive
Summary
This
application note provides the network planner with a list of advantages of
fiber optic communications. All of these advantages result in a cost reduced
relative to that of a non-fiber network. Nearly all implementations of fiber
optic networks invoke more than one of these advantages. With knowledge of
these advantages, the network planner can identify the advantages appropriate
to his application and the associated cost benefits. With such information, the
network planner can make rational and realistic decisions.
Note:
this application note presents information from Chapter 1 of Successful
Fiber Optic Installation, the Pearson Technologies Inc. fiber optic
installation manual.
For
additional information on this comprehensive and valuable training text and
field installation manual, click here.
For
more information on Pearson Technologies Inc. training programs, click here.
Introduction
A fiber network
includes fiber as the transmission medium. Fiber may be the only transmission
medium, as in SONET,
ESCON or FDDI networks. Alternatively, fiber may be
one of several media, as in Ethernet,
Fast Ethernet, and Gigabit Ethernet networks.
Fiber is the
medium of choice because of its nine advantages:
Nearly unlimited bandwidth
Long transmission distance
EMI immunity
RFI immunity
Low cost per bit
Dielectric construction
Small size
Light weight
Ease of installation
Optical fiber
has essentially unlimited bandwidth.
While unlimited bandwidth may sound like a salesperson exaggeration, it is a
realistic and reasonable description of the capacity of the fiber. A study by
Lucent Technologies indicated the theoretical capacity of a single, singlemode fiber is on the order of 200 Tbps, or
200 million Mbps. Such a capacity deserves the term essentially unlimited
bandwidth.
Part of this
high capacity results from the ability to transmit multiple wavelengths
simultaneously. Such transmission is called wavelength division multiplexing (WDM),
coarse wavelength division multiplexing (CWDM),
or dense wavelength division multiplexing (DWDM,
7.6).
WDM is the transmission of two widely spaced
wavelengths, such as 850 nm and 1300 nm on multimode fibers or 1310 nm and 1550 nm on
singlemode fibers. CWDM is the transmission of 3-8 moderately
spaced wavelengths on singlemode fibers. CWDM operates in the wavelength range of 1310 nm to 1560 nm. DWDM is the transmission of many closely
spaced wavelengths, such as 64-200 wavelengths spaced around a wavelength of
1550 nm or in the range of 1310 nm to 1560 nm.
Transmission
Distance
Optical fiber
allows extremely long transmission distance without return to the electrical
regime. While not a current champion result, Williams Communications demonstrated
the ability to transmit 5000 km (3100 miles) in the optical regime. 5000 km is
approximately the distance between Boston MA and Los Angeles CA!
This long
transmission distance is the advantage that drives CATV providers to use fiber. This long
transmission distance enables reduction in the number of satellite farms
necessary to support a service area. In addition, this advantage enables CATV
companies to reduce the number of coax amplifiers between a satellite down link
and set top boxes. This reduction results in reduced costs for equipment and
maintenance and in improved signal quality.
EMI And RFI Immunity
While long
distance transmission capability results primarily from low attenuation rate,
it also results from immunity to electromagnetic interference (EMI)
and radio frequency interference (RFI).
Since optical fibers are immune to interference from such energy, optical
signals can travel long distances without the need for signal correction.
The combination
of multiple wavelengths, low power loss, low pulse dispersion,
and EMI/RFI immunity results in low cost per bit.
This low cost has made fiber the medium of choice for long distance
communication.[1] This low cost has resulted in the
displacement of satellites as the king of long distance communication. Now
satellites are a back up for optical fiber transmission!
At the present time,
many LANs with centralized (or collapsed) back bones, also known as fiber to
the desk networks (FTTD),
have a total initial installed cost that is lower than that of traditional
horizontal UTP, vertical fiber networks.[2] This cost advantage results from a
reduction in the cost of telecommunication rooms that are required within 300
of the nodes. Use of fiber reduces the cost of such rooms and the cost of
support for such rooms.
Finally, the low
cost of optical fiber has led to increased implementation of fiber-to-the-home
(FTTH) networks.
Dielectric Construction
Optical fiber
cables can be made without any conductive elements. Such dielectric
construction eliminates both the initial installed cost and the maintenance cost
of grounds and bonds.
Conductive cables must be grounded and bonded to prevent currents induced by
lightning and ground potential rise from entering a building,
injuring people and damaging electronics.
The small size
of optical fibers and their cables results in reduced system cost. For example,
large cities with filled underground conduit systems have two methods of
increasing telephone capacity: dig up the streets to install more conduits or
replace copper cables with fiber cables. The replacement ratio is 100, 3 inch
diameter, 900 pair cables to one 1 inch diameter fiber cable with single
wavelength transmission. With dense wavelength
division multiplexing (DWDM)
allowing at least 200 wavelengths per fiber, this replacement ratio is 20,000,
3 inch diameter cables with the same 1 inch diameter fiber cable. With 1000
wavelengths per fiber, this ratio is 100,000 3 inch diameter copper cables! The
cost advantage of using fiber instead of digging up streets is extremely large.
Optical fiber
cables are significantly lighter than copper cables. As a result, fiber finds
use in field tactical, shipboard and aircraft applications. In field tactical
applications, reduced weight enables solders to carry increased cable lengths.
Such increased lengths enable placement of electronic monitoring equipment at
the front line while the monitoring personnel are in a safe location. In
addition, the non-radiating nature of optical fibers prevents the enemy from
detecting the equipment location.
In shipboard
applications, the lightweight of optical fiber cables increases the stability
of the ships by reducing the weight above the waterline. Finally, in aircraft
applications, the lightweight increases mission endurance.
Because of their
lightweight and small size, fiber cables are easy to install. In addition,
fiber connector installation methods have advanced sufficiently to enable
installation by junior and senior high school students with minimal training.
Pearson
Technologies FTTD Services
Pearson
Technologies offers a number of services related to fiber to the desk network
design. All of these services save clients more than their costs. These
services include:
Cost comparison
Total network cost
Lowest cost connector installation method
Network component specification
development
Network design training
In the cost
comparison service, Pearson Technologies identifies the cost factors
appropriate to the client network and estimates the actual savings the client
can expect from FTTD. This service
enables clients to make a realistic and practical decision to use FTTD. In
addition, this service eliminates unpleasant surprises.
In the total
network cost service, Pearson Technologies Inc. uses proprietary software to
estimate the total installed cost of a network. This service enables clients to
accurately estimate cost. This service enables clients to query installation
organizations to determine causes of differences from the estimate. These causes
can indicate both reasons to accept increased cost and opportunities to reduce
cost.
In connector
cost calculation, Pearson Technologies provides cost calculations of four
connector installation methods. These estimates enable the client to determine
the method that provides the lowest total installed cost. The lowest cost
connector may not have the lowest total installed cost. Similarly, the
connector with the shortest installation time may not have the lowest total
installed cost. The subtleties that are not part of advertising determine the
total installed cost. Major connector manufacturers have reviewed these
calculations without indicating dispute.
In the network
component specification, Pearson Technologies Inc. develops detailed
specifications that provide the maximum possible network reliability. Based on
the current data communication standards, these specifications make explicit
those performance parameters than can be overlooked by the supplier and the
installer.
In this four
part, four-day network design training program, FiberPro 5, Successful
Fiber Optic Network Design, Pearson Technologies provides fiber network
planners with
The knowledge essential for successful
design
A detailed, eight step design process
Multiple cost estimation techniques and
Experience in development of a complete
design package.
This program
enables network planners to achieve a network design with high reliability, low
installation cost, and low life cycle cost.
Respectfully
submitted for your consideration,
Eric R. Pearson, CPC, CFOS
President
Pearson Technologies Inc.
For Mr. Pearson contact information, click here.
Pearson Technologies Web Sites
http://www.ptnowire.com
http://www.FTTDnow.info
http://www.fiberopticlawsuits.info
http://www.sfoi.info
Contact
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