An optical fiber is a glass or plastic fiber that carries light along its length. They are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss, and also immune to electromagnetic interference. Fibers are also used for illumination, and are wrapped in bundles to carry images. Specially designed fibers are used for other applications, including sensors and fiber lasers.

1. Optical Fibres in Communication
Name:Manhar paramjout singh
Section: D4911
Roll no: A 17
Regd no: 10900912
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2. Contents
1. Introduction
2. Principle of Working
3. Application
4. Manufacturing
5. Process
6. Coatings
7. References
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3. Introduction
An optical fiber is a glass or plastic fiber that carries light along its length.
They are widely used in fiber-optic communications, which permits
transmission over longer distances and at higher bandwidths (data rates) than
other forms of communications. Fibers are used instead of metal wires
because signals travel along them with less loss, and also immune to
electromagnetic interference. Fibers are also used for illumination, and are
wrapped in bundles to carry images. Specially designed fibers are used for
other applications, including sensors and fiber lasers.
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4. Principle of working
An optical fiber is a cylindrical dielectric guide (non conducting waveguide)
that transmits light along its axis, by the process of total internal reflection .
The fiber consists of a core surrounded by a cladding layer, made of dielectric
materials. To confine the optical signal in the core, the refractive index of the
core must be greater than that of the cladding. The boundary between the core
and cladding may either be abrupt, in step index fibre, or gradual, in graded
index fibre.
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5. Applications
1.In communication:
Used to transmit Telephone signals , Internet communications, cable T.V
signals.
2.In Optic Fibre sensors:
used as sensors to measure strain, temperature, pressure and other quantities
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6. Manufacturing
Optical fibers are made from silica, but some other materials, such as
fluorozirconate , fluoroaluminate, and chalcogenide glasses , are used for
longer-wavelength infrared applications.Like other glasses, these glasses have
a refractive index of about 1.5. Typically the difference between core and
cladding is less than one percent.
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7. Process
Standard optical fibers are made by first constructing a large-diameter
preform, with a carefully controlled refractive index profile, and then pulling
the preform to form the long, thin optical fiber. The preform is commonly
made by three chemical vapor deposition methods:-
Inside vapor deposition , Outside vapor deposition, and Vapor axial
deposition.
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8. Coating
Fiber optic coatings are UV-cured urethane acrylate composite materials
applied to the outside of the fiber during the drawing process. The coatings
protect the very delicate strands of glass fiber(about the size of a human
hair)and allow it to survive the rigors of manufacturing, proof testing, cabling
and installation.
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9. References
• http://en.wikipedia.org/wiki/Optical_fiber
• http://en.wikipedia.org/wiki/Fiber-optic_communication
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