421 Fiber Optics Based Computer

8/2/2019 421 Fiber Optics Based Computer

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CONTENTS

PAGE NO.

1. Introduction . 1

2. First a bit history .. 2

3. What is optical fiber .. 3

4. How fiber works ...... 4

5. Types of optical fiber .. 6

5.1 Multimode Fiber . 6

5.1.1 Multimode Step-index Fiber .... 6

5.2 Single-mode Fiber . 7

5.3 Difference between single-mode and multi-mode 7

5.4 Light propagation . 8

6. Optical computing .. 9

7. Optical fiber connectors .. 10

7.1 Connector cleaning .. 10

8. Advantages and Disadvantages of optical fiber . 12

8.1 advantages 12

8.2 disadvantages 14

9. Applications 15

9.1 Optical fiber communication 15

9.2 A fiber-optic Christmas tree . 16

10. Conclusion . 18

11. References ..19


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1.INTRODUCTIONIn recent years it has become apparent that fiber-optics are steadily replacing copper wire

as an appropriate means of communication signal transmission. They span the long distancesbetween local phone systems as well as providing the backbone for many network systems. Other

system users include cable television services, university campuses, office buildings, industrial

plants, and electric utility companies.

A fiber-optic system is similar to the copper wire system that fiber-optics is replacing. The

difference is that fiber-optics use light pulses to transmit information down fiber lines instead of

using electronic pulses to transmit information down copper lines. Looking at the components in a

fiber-optic chain will give a better understanding of how the system works in conjunction with

wire based systems.

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2. FIRST A BIT HISTORY

In 1870, John Tyndall demonstrated that light follows the curve of a stream of water

pouring from a container, it was this simple principle that led to the study and development of

applications for this phenomenon. John Logie Baird patented a method of transmitting light in a

glass rod for use in an early colour TV, but the optical losses inherent in the materials at the time

made it impractical to use. In the 1950's more research and development into the transmission of

visible images through optical fibres led to some success in the medical world, as they began using

them in remote illumination and viewing instruments. In 1966 Charles Kao and George Hockham

proposed the transmission of information over glass fibre, and they also realised that to make it a

practical proposition, much lower losses in the cables were essential. This was the driving force

behind the developments to improve the optical losses in fibre manufacturing, and today optical

losses are significantly lower than the original target set out by Charles Kao and George Hockha

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3. WHAT IS OPTICAL FIBER?


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A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic

cable consists of a bundle of glass threads, each of which is capable of transmitting messages

modulated onto light waves. An optical fiber (orfibre) is a glass or plastic fiber designed to guide

light along its length. Fiber optics is the overlap of applied science and engineering concernedwith such optical fibers. Optical fibers are widely used in fiber-optic communication, which

permits transmission over longer distances and at higher data rates than other forms of wired and

wireless communications. Fibers are used instead of metal wires because signals propagate along

them with less loss, and they are immune to electromagnetic interference. Optical fibers are also

used to form sensors, and in a variety of other applications.

In fibers with large core diameter, the confinement is based on total internal reflection. In

smaller core diameter fibers, (widely used for most communication links longer than 200 meters)

the fiber acts as a waveguide. There are many different designs of optical fibers, including graded-

index optical fibers, step-index optical fibers which are characteristics of an optical fiber and

different types of optical fiber as singlemode fibers (SMF) in which there are three kinds of fibers,

non-dispersion shifted fibres (NDSF), nonzero dispersion-shifted fibers (NZDSF) and dispersion-

shifted fibers (DSF), multimode fibers (MMF), birefringentpolarization-maintaining fibers (PMF)

and more recentlyphotonic crystal fibers (PCF), with the design and the wavelength of the light

propagating in the fiber dictating whether or not it will be multi-mode optical fiberorsingle-mode

optical fiber. Because of the mechanical properties of the more common glass optical fibers,

special methods of splicing fibers and of connecting them to other equipment are needed.

Manufacture of optical fibers is based on partially melting a chemically doped preform and pullingthe flowing material on a draw tower. Fibers are built into different kinds of cables depending on

how they will be used.

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4. HOW FIBER WORKS
http://www.webopedia.com/TERM/f/data.htmlhttp://www.webopedia.com/TERM/f/fiber_optics.htmlhttp://www.webopedia.com/TERM/f/fiber_optics.htmlhttp://www.webopedia.com/TERM/f/modulate.htmlhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Applied_sciencehttp://en.wikipedia.org/wiki/Engineeringhttp://en.wikipedia.org/wiki/Fiber-optic_communicationhttp://en.wikipedia.org/wiki/Electromagnetic_interferencehttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Total_internal_reflectionhttp://en.wikipedia.org/wiki/Meterhttp://en.wikipedia.org/wiki/Waveguidehttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Step-index_profilehttp://en.wikipedia.org/wiki/Singlemode_fiberhttp://en.wikipedia.org/wiki/Nonzero_dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Multimode_fiberhttp://en.wikipedia.org/wiki/Polarization-maintaining_optical_fiberhttp://en.wikipedia.org/wiki/Photonic_crystal_fibershttp://en.wikipedia.org/wiki/Multi-mode_optical_fiberhttp://en.wikipedia.org/wiki/Single-mode_optical_fiberhttp://en.wikipedia.org/wiki/Single-mode_optical_fiberhttp://en.wikipedia.org/wiki/Cablehttp://www.webopedia.com/TERM/f/data.htmlhttp://www.webopedia.com/TERM/f/fiber_optics.htmlhttp://www.webopedia.com/TERM/f/fiber_optics.htmlhttp://www.webopedia.com/TERM/f/modulate.htmlhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Applied_sciencehttp://en.wikipedia.org/wiki/Engineeringhttp://en.wikipedia.org/wiki/Fiber-optic_communicationhttp://en.wikipedia.org/wiki/Electromagnetic_interferencehttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Total_internal_reflectionhttp://en.wikipedia.org/wiki/Meterhttp://en.wikipedia.org/wiki/Waveguidehttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Step-index_profilehttp://en.wikipedia.org/wiki/Singlemode_fiberhttp://en.wikipedia.org/wiki/Nonzero_dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Dispersion-shifted_fiberhttp://en.wikipedia.org/wiki/Multimode_fiberhttp://en.wikipedia.org/wiki/Polarization-maintaining_optical_fiberhttp://en.wikipedia.org/wiki/Photonic_crystal_fibershttp://en.wikipedia.org/wiki/Multi-mode_optical_fiberhttp://en.wikipedia.org/wiki/Single-mode_optical_fiberhttp://en.wikipedia.org/wiki/Single-mode_optical_fiberhttp://en.wikipedia.org/wiki/Cable


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Fiber optic technology is based on the use of light energy to transmit data. Basically, the

encoded data is converted from electrical signals to optical light pulses and then transmitted

through the medium to its destination, where it is then converted back. From this, we can see that

there are basically three mainelements in any fiber optic data link: a transmitter, an optical cable(the transmission medium), and a receiver. The transmitter handles the conversion from electrical

to light energy, the optical cable carries the light waves, and the receiver handles the conversion

from light pulses back to the original electrical format.

After translating the electrical signals, the transmitter uses either a light emitting diode

(LED) or an injection laser diode (ILD) to generate the light pulses. Using a lens, this light energy

is then sent down the fiber optic cable. The principle that makes this possible is referred to as total

internal reflection. According to John Huber in an article in R&D Magazine, this principle of totalinternal reflection states that when the angle of incidence exceeds a critical value, light cannot get

out of the glass; instead, the light bounces back in (Huber 115). This happens when two materials

with different refractive indices cause the angle of incidence to be too large for refraction

(bending) of light to take place. Since the light cannot be bent and exit the material, this means that

100 percent is reflected back. Thus, when a fiber optic cable, which consists of a glass or plastic

core surrounded by a cladding with a lower refractive index, receives a light ray, the light ray is

confined and travels down the core to the receiving end. Simply put, the difference in the materials

used for the core and the cladding make an extremely reflective surface at the point where they

interface, which makes the principle of total internal reflection possible. This is the fundamental

concept behind all fiber optic transmissions.

In addition to the core and the cladding, a fiber optic cable also has an outer jacket that

protects it from abrasion and other forces. Most high end cabling will also have a protective buffer

and strength material between the cladding and the outer jacket. These outer layers are added to

help protect the fragile core and cladding from damage. There are two common types of cabling

used for most fiber optic applications: single-mode and multi-mode. Single-mode fiber is generally

used for long distance communications. It has a narrower core diameter, generally 8-10 microns,

with a 125-micron cladding. Single-mode optical fiber only allows one mode of light to traveldown its core. On the other hand, multi-mode fiber generally has a 62.5-micron core diameter with

a 125-micron cladding.

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In order to receive the signal and then convert it back to its original format, a fiber optic

receiver uses a phototransistor to convert the light energy into an electrical current. This current is


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then sent into an amplifier in order to boost the electrical signal back to its original level, and then

a digitizer circuit is used to convert the signal into the appropriate digital voltage levels to be used

by the external logic. At this point, the electronic signal is ready to be received by the

communications device, whether it is a switch, router, computer, etc.

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5. TYPES OF OPTICAL FIBER


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Understanding the characteristics of different fiber types aides in understanding the

applications for which they are used. Operating a fiber optic system properly relies on knowing

what type of fiber is being used and why. There are two basic types of fiber: multimode fiber and

single-mode fiber. Multimode fiber is best designed for short transmission distances, and is suited

for use in LAN systems and video surveillance. Single-mode fiber is best designed for longer

transmission distances, making it suitable for long-distance telephony and multichannel television

broadcast systems.

5.1. Multimode Fiber

Multimode fiber, the first to be manufactured and commercialized, simply refers to the fact that

numerous modes or light rays are carried simultaneously through the waveguide. Modes result from the

fact that light will only propagate in the fiber core at discrete angles within the cone of acceptance. This

fiber type has a much larger core diameter, compared to single-mode fiber, allowing for the larger number

of modes, and multimode fiber is easier to couple than single-mode optical fiber. Multimode fiber may be

categorized as step-index or graded-index fiber .

5.1.1. Multimode Step-index Fiber

The principle of total internal reflection applies to multimode step-index fiber. Because the

coresindex of refraction is higher than the claddings index of refraction, the light that enters at

less than the critical angle is guided along the fiber.

Three different lightwaves travel down the fiber. One mode travels straight down the center

of the core. A second mode travels at a steep angle and bounces back and forth by total internal

reflection. The third mode exceeds the critical angle and refracts into the cladding. Intuitively, it

can be seen that the second mode travels a longer distance than the first mode, causing the two

modes to arrive at separate times.

This disparity between arrival times of the different light rays is known as dispersion, and

the result is a muddied signal at the receiving end. For a more detailed discussion of dispersion, see"Dispersion in Fiber Optic Systems;" however, it is important to note that high dispersion is an

unavoidable characteristic of multimode step-index fiber. . 6

5.2. Single-mode Fiber
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Single-mode fiber allows for a higher capacity to transmit information because it can retain

the fidelity of each light pulse over longer distances, and it exhibits no dispersion caused by

multiple modes. Single-mode fiber also enjoys lower fiberattenuationthan multimode fiber. Thus,

more information can be transmitted per unit of time. Like multimode fiber, early single-modefiber was generally characterized as step-index fiber meaning the refractive index of the fiber core

is a step above that of the cladding rather than graduated as it is in graded-index fiber. Modern

single-mode fibers have evolved into more complex designs such as matched clad, depressed clad

and other exotic structures.

Single-mode fiber has disadvantages. The smaller core diameter makes coupling light into

the core more difficult. The tolerances for single-mode connectorsand splices are also much more

demanding.

5.3. What's the difference between single-mode and multi-mode?

With copper cables larger size means less resistance and therefore more current, but with

fibre the opposite is true. To explain this we first need to understand how the light propagates

within the fibre core.

Figure 5.3 7
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5.4. LIGHT PROPAGATION

Light travels along a fiber cable by a process called 'Total Internal Reflection' (TIR), this is

made possible by using two types of glass which have different refractive indexes. The inner core

has a high refractive index and the outer cladding has a low index. This is the same principle as thereflection you see when you look into a pond. The water in the pond has a higher refractive index

than the air, and if you look at it from a shallow angle you will see a reflection of the surrounding

area, however, if you look straight down at the water you can see the bottom of the pond. At some

specific angle between these two view points the light stops reflecting off the surface of the water

and passes through the air/water interface allowing you to see the bottom of the pond. In multi-

mode fibres, as the name suggests, there are multiple modes of propagation for the rays of light.

These range from low order modes which take the most direct route straight down the middle, to

high order modes which take the longest route as they bounce from one side to the other all the

way down the fibr

This has the effect of scattering the signal because the rays from one pulse of light, arrive at

the far end at different times, this is known as Intermodal Dispersion (sometimes referred to as

Differential Mode Delay, DMD). To ease the problem, graded index fibres were developed. Unlike

the examples above which have a definite barrier between core and cladding, these have a high

refractive index at the centre which gradually reduces to a low refractive index at the

circumference. This slows down the lower order modes allowing the rays to arrive at the far end

closer together, thereby reducing intermodal dispersion and improving the shape of the signal.

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6. OPTICAL COMPUTING


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An optical computer is a computer that uses light instead of electricity (i.e. photons rather

than electrons) to manipulate, store and transmit data. Photons have fundamentally different

physical properties than electrons, and researchers have attempted to make use of these properties

to produce computers with performance and/or capabilities greater than those of electroniccomputers. Optical computer technology is still in the early stages: functional optical computers

have been built in the laboratory, but none have progressed past the prototype stage.

Most research projects focus on replacing current computer components with optical

equivalents, resulting in an optical digital computer system processing binary data. This approach

appears to offer the best short-term prospects for commercial optical computing, since optical

components could be integrated into traditional computers to produce an optical/electronic hybrid.

Other research projects take a non-traditional approach, attempting to develop entirely newmethods of computing that are not physically possible with electronics.

An optical computer is a device that uses visible light or infrared beams, rather than electric

current, to perform digital computations.Optical computers promise speeds, which will be

thousands, even millions of times faster than those of today's most efficient supercomputers.The

optical computer could revolutionize computing in much the same way that the semiconductor chip

revolutionized electronics 30 years ago.An electric current flows at only about 10 percent of the

speed of light.

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7. OPTICAL FIBER CONNECTORS
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Fiber optic connectors have traditionally been the biggest concern in using fiber optic

systems. While connectors were once unwieldy and difficult to use, connector manufacturers have

standardized and simplified connectors greatly. This increasing user-friendliness has contributed to

the increase in the use of fiber optic systems; it has also taken the emphasis off the proper care and

handling of optical connectors.

Fiber-to-fiber interconnection can consist of a splice, a permanent connection, or a

connector, which differs from the splice in its ability to be disconnected and reconnected. Fiber

optic connector types are as various as the applications for which they were developed. Different

connector types have different characteristics, different advantages and disadvantages, and

different performance parameters.

7.1. connector cleaning

Another important thing to remember in handling fiber optic connectors is that the fiber

end face and ferrule must be absolutely clean before it is inserted into a transmitter or receiver.

Dust, lint, oil (from touching the fiber end face), or other foreign particles obscure the end face,

compromising the integrity of the optical signal being sent over the fiber. From the optical signals

point-of-view, dirty connections are like dirty windows. Less light gets through a dirty window

than a clean one.

It is hard to conceive of the size of a fiber optic connector core. Single-mode fibers have

cores that are only 8-9 m in diameter. As a point of reference, a typical human hair is 50-75 m

in diameter, approximately 6-9 times larger! Dust particles can be 20 m or larger in diameter.

Dust particles smaller than 1 m can be suspended almost indefinitely in the air. A 1 m dust

particle landing on the core of a single-mode fiber can cause up to 1 dB of loss. Larger dust

particles (9 m or larger) can completely obscure the core of a single-mode fiber. Fiber optic

connectors need to be cleaned every time they are mated and unmated; it is essential that fiber

optics users develop the necessary discipline to always clean the connectors before they are mated.

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Connector damage can occur if foreign particles are caught in the end face area of mated

connectors.Connector cleaning is simply completed by wiping the connector ferrule and end face

with some isopropyl alcohol and a lint free tissue. Another option for connector cleaning is the
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cassette type cleaners which use a dry tape system where the tape is advanced every time the

cassette is opened ensuring the clean section of tape is used each time.

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ABSTRACT

With the growth of computing technology the need of high performance Computers (HPC)

have significantly increased.The use of light for the transmission of information is far from a new

idea. Fiber optics is a relatively new technology that uses rays of light to send information over

hair-thin fibers at blinding speeds. These fibers are used as an alternative to conventional copper

wire in a variety ofapplications such as those associated with security, telecommunications,

instrumentation and control, broadcast or audio/visual systems.


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Optical computing technology is, in general, developing in two directions. One approach is

to build computers that have the same architecture as present day computers but using optics that is

Electro optical hybrids. Another approach is to generate a completely new kind of computer, which

can perform all functional operations in optical mode.


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8. ADVANTAGES AND DISADVANTAGES OF

FIBER OPTIC SYSTEMS

8.1. ADVANTAGES

Because of the Low loss, high bandwidth properties of fiber cable they can

be used over greater distances than copper cables, in data networks this can be as

much as 2km without the use of repeaters. Their light weight and small size also

make them ideal for applications where running copper cables would be

impractical, and by using multiplexors one fibre could replace hundreds of copper

cables. This is pretty impressive for a tiny glass filament, but the real benefits in the

data industry are its immunity to Electro Magnetic Interference (EMI), and the fact

that glass is not an electrical conductor. Because fibre is non-conductive, it can be

used where electrical isolation is needed, for instance between buildings where

copper cables would require cross bonding to eliminate differences in earth

potentials. Fibres also pose no threat in dangerous environments such as chemical

plants where a spark could trigger an explosion. Last but not least is the security

aspect, it is very, very difficult to tap into a fibre cable to read the data signals.

fiber optic systems have many attractive features that are superior to

electrical systems. These include improved system performance, immunity to

electrical noise, signal security, and improved safety and electrical isolation.

Fiber optic transmission systems - a fiber optic transmitter and receiver,

connected by fiber optic cable - offer a wide range of benefits not offered by

traditional copper wire or coaxial cable. These include:

The ability to carry much more information and deliver it with greater

fidelity than either copper wire or coaxial cable.

Fiber optic cable can support much higher data rates, and at greater

distances, than coaxial cable, making it ideal for transmission of serial digital data.

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The fiber is totally immune to virtually all kinds of interference,

including lightning, and will not conduct electricity. It can therefore come in direct


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contact with high voltage electrical equipment and power lines. It will also not

create ground loops of any kind.

As the basic fiber is made of glass, it will not corrode and is unaffected by

most chemicals. It can be buried directly in most kinds of soil or exposed to most

corrosive atmospheres in chemical plants without significant concern.

Since the only carrier in the fiber is light, there is no possibility of a spark

from a broken fiber. Even in the most explosive of atmospheres, there is no fire

hazard, and no danger of electrical shock to personnel repairing broken fibers.

Fiber optic cables are virtually unaffected by outdoor atmospheric

conditions, allowing them to be lashed directly to telephone poles or existing

electrical cables without concern for extraneous signal pickup.

A fiber optic cable, even one that contains many fibers, is usually much

smaller and lighter in weight than a wire or coaxial cable with similar information

carrying capacity. It is easier to handle and install, and uses less duct space. (It can

frequently be installed without ducts.)

Fiber optic cable is ideal for secure communications systems because it is

very difficult to tap but very easy to monitor. In addition, there is absolutely no

electrical radiation from a fiber.

Fiber optics is a particularly popular technology for local-area networks. In

addition, telephone companies are steadily replacing traditional telephone lines with

fiber optic cables. In the future, almost all communications will employ fiberoptics.

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8.2. DISADVANTAGES
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Because of the relative newness of the technology, fiber optic components

are expensive. Fiber optic transmitters and receivers are still relatively expensive

compared to electrical interfaces. The lack of standardization in the industry has

also limited the acceptance of fiber optics. Many industries are more comfortablewith the use of electrical systems and are reluctant to switch to fiber optics.

However, industry researchers are eliminating these disadvantages.

Standards committees are addressing fiber optic part and test

standardization.

The cost to install fiber optic systems is falling because of an increase in

the use of fiber optic technology. Published articles, conferences, and lectures on

fiber optics have begun to educate managers and technicians. As the technology

matures, the use of fiber optics will increase because of its many advantages overelectrical systems.

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9. APPLICATION IN DIFFERENT FIELDS:


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9.1. Optical fiber communication

Optical fiber can be used as a medium for telecommunication and

networking because it is flexible and can be bundled as cables. It is especiallyadvantageous for long-distance communications, because light propagates through

the fiber with little attenuation compared to electrical cables. This allows long

distances to be spanned with few repeaters. Additionally, the light signals

propagating in the fiber can be modulated at rates as high as 40 Gb/s and each fiber

can carry many independent channels, each by a different wavelength of light

(wavelength-division-multiplex WDM). In total, a single fiber-optic cable can carry

data at rates as high as 14.4 Pb/s (circa 14 million Gb/s). Over short distances, such

as networking within a building, fiber saves space in cable ducts because a single

fiber can carry much more data than a single electrical cable. Fiber is also immune

to electrical interference, which prevents cross-talk between signals in differentcables and pickup of environmental noise. Also, wiretapping is more difficult

compared to electrical connections, and there are concentric dual core fibers that

are said to be tap-proof. Because they are non-electrical, fiber cables can bridge

very high electrical potential differences and can be used in environments where

explosive fumes are present, without danger of ignition.

Although fibers can be made out of transparent plastic, glass, or a

combination of the two, the fibers used in long-distance telecommunicationsapplications are always glass, because of the lower optical attenuation. Both multi-

mode and single-mode fibers are used in communications, with multi-mode fiber

used mostly for short distances (up to 500 m), and single-mode fiber used for

longer distance links. Because of the tighter tolerances required to couple light into

and between single-mode fibers (core diameter about 10 micrometers), single-mode

transmitters, receivers, amplifiers and other components are generally more

expensive than multi-mode components.

Optical fibers can be used as sensors to measure strain, temperature,

pressure and other parameters. The small size and the fact that no electrical power

is needed at the remote location gives the fiber optic sensor advantages to

conventional electrical sensor in certain applications. 15
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Optical fibers are used as hydrophones for seismic or SONAR

applications. Hydrophone systems with more than 100 sensors per fiber cable have

been developed. Hydrophone sensor systems are used by the oil industry as well as

a few countries' navies. Both bottom mounted hydrophone arrays and towed

streamer systems are in use. The German company Sennheiser developed a

microphone working with a laserand optical fibers.

Optical fiber sensors for temperature and pressure have been developed

for downhole measurement in oil wells. The fiber optic sensor is well suited for this

environment as it is functioning at temperatures too high for semiconductor sensors

(Distributed Temperature Sensing).

Another use of the optical fiber as a sensor is the optical gyroscope which

is in use in the Boeing 767 and in some car models (for navigation purposes) and

the use in Hydrogen microsensors.

Fiber-optic sensors have been developed to measure co-located

temperature and strain simultaneously with very high accuracy. This is particularly

useful to acquire information from small complex structures.

9.2. A fiber-optic christmas tree

Optical fiber is also used in imaging optics. A coherent bundle of fibers is

used, sometimes along with lenses, for a long, thin imaging device called an

endoscope, which is used to view objects through a small hole. Medical endoscopes

are used for minimally invasive exploratory or surgical procedures (endoscopy).

Industrial endoscopes are used for inspecting anything hard to reach, such as jet

engine interiors.

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An optical fiber doped with certain rare-earth elements such as erbium can

be used as the gain medium of a laser or optical amplifier. Rare-earth doped optical
http://en.wikipedia.org/wiki/Hydrophonehttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Sennheiserhttp://en.wikipedia.org/wiki/Laser_microphonehttp://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Distributed_Temperature_Sensinghttp://en.wikipedia.org/wiki/Fibre_optic_gyroscopehttp://en.wikipedia.org/wiki/Boeing_767http://en.wikipedia.org/wiki/Hydrogen_microsensorhttp://en.wikipedia.org/wiki/Hydrophonehttp://en.wikipedia.org/wiki/Sonarhttp://en.wikipedia.org/wiki/Sennheiserhttp://en.wikipedia.org/wiki/Laser_microphonehttp://en.wikipedia.org/wiki/Laserhttp://en.wikipedia.org/wiki/Distributed_Temperature_Sensinghttp://en.wikipedia.org/wiki/Fibre_optic_gyroscopehttp://en.wikipedia.org/wiki/Boeing_767http://en.wikipedia.org/wiki/Hydrogen_microsensor


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fibers can be used to provide signal amplification by splicing a short section of

doped fiber into a regular (undoped) optical fiber line. The doped fiber is optically

pumped with a second laser wavelength that is coupled into the line in addition to

the signal wave.

Both wavelengths of light are transmitted through the doped fiber, which

transfers energy from the second pump wavelength to the signal wave. The process

that causes the amplification is stimulated emission.

Optical fibers doped with a wavelength shifter are used to collect

scintillation light in physics experiments.

Optical fiber can be used to supply a low level of power (around one watt)

to electronics situated in a difficult electrical environment. Examples of this are

electronics in high-powered antenna elements and measurement devices used in

high voltage transmission equipment.

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10. CONCLUSION

The applications of the fiber optics field are still emerging and developing so rapidly that, it

is impossible to keep track each and every innovations and inventions. All the above compilationsgives idea about the tremendous potential associated with this field.The future is not so distant

when scientists and researchers will come up with more and more futuristic products and

applications using optical fibers.

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11. References[1] T Okoshi and K Kikuchi, Coherent optical fiber communication (Kluwer Academic, Boston,

1988)

[2] A Hasegawa, Optical solitons in fibers (Springer Verlag, New York, 1989)

[3] S E Millar and I P Kaminow, eds, Optical fiber telecommunications - II(Academic, New

York 1988)

[4] G P Agrawal,Nonlinear fiber optics (Academic, New York, 1989)

[5] C Yeh,Handbook of fiber optics (Academic, New York, 1990)

[6] G P Agrawal,Fiber optic communication systems (John Wiley, Singapore, 1993)

[7] N S Bergano and C R Davidson, Wavelength division multiplexing in long-haul transmissionsystems,J. Lightwave Tech. 14, 1299 (1996)

[8] E Desurvire,Erbium doped fiber amplifiers (John Wiley, New York, 1994)

[9] R J Hoss and EA Lacy,Fiber optics 2nd edition (Prentice Hall, New Jersey, 1993)

[10] M Nakazawa, Soliton transmission in telecommunication networks,IEEE. Communication

magazine, March 24 (1994)

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421 Fiber Optics Based Computer

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