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Optical Fibre

An optical fibre ( or fiber ) is a glass or plasticfibre that carries light along its length.

It has two main component layers: A Core &A Cladding.

Light is kept in th core of optical fibre.

Cladding is for the protection of fibre.

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Advantages of Optical fibre.

Thinner than other tubes.

Less expensive

High Carrying Capacity.Provides a very large Bandwidth

Less signal distortion

Non- flammableLight Weight

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Fibre Optic Disadvantages.

Expensive over short distance.

Very high Installation charges

& demands high skills.

Adding additional nodes is

difficult.

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Areas Of Application

Telecommunication

Local Area Networks

Cable TVCCTV

Optical Fibre Sensors

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Optical Fibre Construction

Core: Thin Glass Center of

the fibre where light travels.

Cladding: Outer OpticalMaterial surrounding the

Core.

Buffer Coating: PlasticCoating that protects the

Fibre.

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Material Used.

The Core , & the lower refractiveindex Cladding , are typically made of

high quality silica glass, though theycan be both made of plastic as well.

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Mode Of Propagation

Two main categories that are used in Fibre

Optic Communications are:

Multi-mode Optical Fibre

Single Mode Optical Fibre

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Index Profile

The boundary between

the core and cladding

may either be abrupt,

in step-index fiber, or

gradual, in graded-

index fiber.

http://en.wikipedia.org/wiki/Step-index_profilehttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://en.wikipedia.org/wiki/Graded-index_fiberhttp://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/Step-index_profilehttp://en.wikipedia.org/wiki/Step-index_profilehttp://en.wikipedia.org/wiki/Step-index_profilehttp://en.wikipedia.org/wiki/Step-index_profile

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Step-Index

A step-index fiber has a central core with a

uniform refractive index. An outside cladding

that also has a uniform refractive index

surrounds the core;

However, the refractive index of the cladding

is less than that of the central core.

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Graded-Index

In graded-index fiber, the index of refraction

in the core decreases continuously between

the axis and the cladding. This causes light

rays to bend smoothly as they approach the

cladding, rather than reflecting abruptly from

the core-cladding boundary.

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Fiber Optic Communication

It is a method of transmitting information

from one place to another by sending light

through an optical fiber.

The light forms an electromagnetic carrier

wavethat is modulatedto carry information.

http://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Carrier_wavehttp://en.wikipedia.org/wiki/Carrier_wavehttp://en.wikipedia.org/wiki/Modulationhttp://en.wikipedia.org/wiki/Modulationhttp://en.wikipedia.org/wiki/Carrier_wavehttp://en.wikipedia.org/wiki/Carrier_wavehttp://en.wikipedia.org/wiki/Carrier_wavehttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Optical_fiberhttp://en.wikipedia.org/wiki/Light

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Block Diagram of OFC

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Use of OFC in Railways.

To optimize train scheduling.

Speed measurement.

Signal distribution by FBG.Traffic light monitoring.