Throughout time, speed and efficiency in the
telecommunications industry has progressed at a
rapid pace due to fiber optic technology. In 1979,
AT&T revolutionized the telecommunications
industry by producing a medium for data
transmission which used light, called fiber optic
cable. This medium created a bandwidth of 44.736
Mbps and could multiplex 672 trunk circuits onto
one fiber (Cole, 2000). However, this invention
was only the beginning of a great addition to
telecommunications, one that would change the
industry forever. Even though AT&T introduced
fiber optic technology in 1979, they werent the
first company to think of such a creative idea.
The concept of exchanging data by the use of light
was thought of by Alexander Graham Bell in the
late 1800s. Bell always thought of possibilities
that pulses of light could transmit voice signals,
but Bell never had a dependable light source to
test the idea (Cheo, 1990).
In 1880, Bell patented
a phone using optical transmission called the
Photophone. Bells invention failed because it used
air as the medium to transmit light, rather than
the glass fibers that are used today. Copper wire
was simply more reliable than Bells invention at
the time, leading to the failure of his Photophone
(Hecht, 1999). Expanding on Bells idea, English
scientist John Logie Bard and United States
scientist Clarence W. Hansell patented the idea of
using hollow glass pipes to transmit television
images in the 1920s. However, the tubes patented
were very poor quality and experienced signal loss
Bard and Hansell also ran into the
same problem Bell did, not having a constant,
intense light source (Hecht, 1999). Solving Bard
and Hansells problem, engineers at Laser Diode
Labs invented the continuous wave laser in 1975.
This laser was smaller than a grain of sand, but
made the use of fiber optics in telephony
possible. In 1987, another great achievement was
made in the fiber optics industry; this
achievement was the erbium-doped fiber amplifier,
which allowed multiple channels of light to
coexist on a single circuit. This fiber amplifier
provided enough channels for one fiber cable to
handle 80 million telephone calls simultaneously
(Greatest, 2000). Today, fiber optic technology
transmits data by sending light pulses down thin
strands of glass or plastic fiber using a laser or
light emitting diode (LED). Strands of fiber are
composed of three main elements: the core,
cladding, and buffer coating.
The inside piece of
the fiber is called the core as can be seen from
the picture below. A fibers core is the path where
the light travels. Surrounding the core is optical
material called cladding. Cladding continually
reflects light pulses causing the pulses to travel
smoothly through the fiber core. The buffer
coating serves as a protection for the cladding
and the core by protecting it from outside
elements such as moisture (Fotec, 1996). The glass
fibers that compose the core of the fiber strands
used in present-day fiber optic systems are mostly
based on extremely pure sand.
Fiber made from
ordinary glass used in windows is so dirty that
impurities reduce signal intensity by a factor of
one million in only about 16 feet of fiber. These
impurities must be removed before useful long-haul
fibers can be made (Stafford, 1988). Even
perfectly pure glass is not completely
transparent. Fiber optic loss is much lower than
copper wire loss, yet some loss does still exist.
Light pulses can be lossed during transmission by
one of two ways. The first way, occurring at
shorter wavelengths, is a scattering caused by
unavoidable density changes within the fiber. When
the light changes mediums, the change in density
The other is a longer
wavelength absorption caused by atomic vibrations
within the glass fiber (Stafford, 1988). The two
main types of fiber in use today are single-mode
and multi-mode fiber. The difference in
single-mode and multi-mode fiber is in the size of
the core. Single-mode fiber has a core with a
diameter of 9 microns. Single-mode fiber typically
is used to transmit light pulses that have
wavelengths of 1300 to 1500 nanometers. This type
of fiber is used primarily for the transmission of
Multi-mode fiber has a core with a diameter
of approximately 62.5 microns. This type of fiber
is used primarily in local area network (LAN)
connections and carries wavelengths of 850-1300
nanometers (Fotec, 1996). Presently, wave division
multiplexing (WDM) technology is used in fiber
optics system. WDM breaks the different colors of
light into multiple frequencies so they can
coexist on the same channel. Each color of light
has its own frequency. Currently, WDM has 16
different frequencies that are used (Cole, 2000).
Fiber optics technology has many advantages.
of the main advantages fiber optic cable has over
electrical wires is the distance the repeaters are
spaced apart. In electrical systems, repeaters are
needed approximately every mile, whereas a fiber
optics system only needs a repeater about every
4-7 miles. Low speed systems can have repeaters
spaced up to 62 miles apart (Microsoft, 1997).
Fiber can also handle many more calls that copper
wire. Two fibers in a fiber cable can handle more
calls that a entire single copper wire can
(Stafford, 1988). A typical fiber optic cable,
approximately 1.25 cm in diameter can carry in
excess of 2.3 million simultaneous voice
calls…about 484 times as much information as 10
cm copper cable (Concise, 1994). Another great
advantage of a fiber optics system is the fact
that it is noise free.
Unlike electrical systems,
fiber optics systems are not susceptible to
electromagnetic induction (Cole, 2000). Since this
is true, many fiber optics cables can be grouped
next to each other without causing interference to
one another. They can also be placed by large
power sources; something that copper wire cannot
be exposed to because of the interference.
Furthermore, fiber optic technology is very
secure. It cannot be tapped without detection
unlike copper wire. Fiber optics technology has
extremely low error or data loss compared to
copper wire also. Lack of radiation is also
another great benefit of using fiber optics
technology (Concise, 1994).
Fiber is also not very
susceptible to outside elements such as copper
cable is. Therefore fiber it can be buried easily.
Fiber optics systems have also been proven less
expensive to maintain when they become damaged
(Stafford, 1988). They have also been proven to
last longer when properly insulated (Concise,
1994). One of the few drawbacks to fiber optics
today is cost. Fiber optics systems are still too
expensive to install on the local loop. Telephone
companies can cost justify fiber links where there
is a lot of customers such as in metropolitan
areas, but running fiber links into homes cannot
be justified because of outrageous terminal
equipment costs (Hecht, 1999).
are estimated to drop, allowing fiber cable to be
installed throughout the entire telephony system.
The only other drawback to fiber optic technology
is the fact that it is more fragile than copper
wire (Concise, 1994). This can be solved by proper
insulation and handling. In 1988, the first
transoceanic fiber cable was laid out on the
bottom of the Atlantic Ocean. This cable costs a
mere $10,000 a circuit compared with the first
Trans-Atlantic copper cable laid in 1956 for
$1,000,000 a circuit (Greatest, 2000). At this
cost reduction, fiber cable is making global
communication much less costly and more efficient,
making worldwide data communication limitless.
Future enhancements in fiber optics look very
promising. With current progress, fiber systems
are doubling in capacity every one to two years
Fiber optics use is increasingly
being used in every aspect of communications. When
AT&T started using fiber optics in 1979,
telephony was revolutionized. Today, the fiber
optics industry is growing faster and faster. Over
90 % of long distance calls are now transmitted
via fiber optics (Concise, 1994). Hopefully,
someday there will be no limit to speed in the
telecommunications industry because of fiber
optics. Works Cited Cheo, P.
(1990). Fiber Optics
and Optoelectronics: Second Edition. Upper Saddle
River, NJ: Prentice Hall. Cole, M. (2000).
Introduction to Telecommunications: Voice, Data,
and the Internet. Upper Saddle River, NJ: Prentice
Concise Columbia Electronic Encyclopedia.
(1994). Fiber Optic Systems:OVERVIEW. Available
Fotec. (1996). Lennie Lightwaves Guide To Fiber
Optic Jargon. [Online Web Site].
WWW.http://www.fotec.com/len 01.htm Greatest
Achievements. (2000). Greatest Achievements – 18.
Laser and Fiber Optics. [Online Web Site].
greatachievements/ga 18 2.html Hecht, J. (1999).
Fiber Optic History. [Online Web Site].
tml Microsoft Encarta Online. (1997). Fiber
Optics. [Online Web Site]. Available
p;pg=2&ti=761566545 Stafford, E., & McCann
Fiber Optics and Laser Handbook. Blue
Ridge Summit, PA: Tab Books, Inc..
Research essay sample on An Introduction To Fiber Optics Technology