Optical Fiber
Content
7/14/2016
Optical fiber Wikipedia, the free encyclopedia
Optical fiber
From Wikipedia, the free encyclopedia
An optical fiber (or optical fibre) is a flexible, transparent fiber made by
drawing glass (silica) or plastic to a diameter slightly thicker than that of a
human hair.[1] Optical fibers are used most often as a means to transmit
light between the two ends of the fiber and find wide usage in fiberoptic
communications, where they permit transmission over longer distances and
at higher bandwidths (data rates) than wire cables. Fibers are used instead
of metal wires because signals travel along them with lesser amounts of
lossÍž in addition, fibers are also immune to electromagnetic interference, a
problem from which metal wires suffer excessively.[2][3] Fibers are also
used for illumination, and are wrapped in bundles so that they may be used
to carry images, thus allowing viewing in confined spaces, as in the case of
a fiberscope.[4] Specially designed fibers are also used for a variety of other
applications, some of them being fiber optic sensors and fiber lasers.[5]
Optical fibers typically include a transparent core surrounded by a
transparent cladding material with a lower index of refraction. Light is kept
in the core by the phenomenon of total internal reflection which causes the
fiber to act as a waveguide.[6] Fibers that support many propagation paths
or transverse modes are called multimode fibers (MMF), while those that
support a single mode are called singlemode fibers (SMF). Multimode
fibers generally have a wider core diameter and are used for shortdistance
communication links and for applications where high power must be
transmitted. Singlemode fibers are used for most communication links
longer than 1,000 meters (3,300 ft).
An important aspect of a fiber optic communication is that of extension of
the fiber optic cables such that the losses brought about by joining two
different cables is kept to a minimum.[7] Joining lengths of optical fiber
often proves to be more complex than joining electrical wire or cable and
involves careful cleaving of the fibers, perfect alignment of the fiber cores,
and the splicing of these aligned fiber cores. For applications that demand a
permanent connection a mechanical splice which holds the ends of the
fibers together mechanically could be used or a fusion splice that uses heat
to fuse the ends of the fibers together could be used. Temporary or semi
permanent connections are made by means of specialized optical fiber
connectors.[8]
A bundle of optical fibers
Fiber crew installing a 432count
fiber cable underneath the streets of
Midtown Manhattan, New York City
The field of applied science and engineering concerned with the design and
application of optical fibers is known as fiber optics.
Contents
A TOSLINK fiber optic audio cable
with red light being shone in one end
transmits the light to the other end
1 History
2 Uses
2.1 Communication
https://en.wikipedia.org/wiki/Optical_fiber
1/22
7/14/2016
Optical fiber Wikipedia, the free encyclopedia
2.1 Communication
2.2 Sensors
2.3 Power transmission
2.4 Other uses
3 Principle of operation
3.1 Index of refraction
3.2 Total internal reflection
3.3 Multimode fiber
3.4 Singlemode fiber
3.5 Specialpurpose fiber
4 Mechanisms of attenuation
4.1 Light scattering
4.2 UVVisIR absorption
5 Manufacturing
5.1 Materials
5.2 Process
5.3 Coatings
6 Practical issues
6.1 Cable construction
6.2 Termination and splicing
6.3 Freespace coupling
6.4 Fiber fuse
6.5 Chromatic dispersion
7 See also
8 References
9 Further reading
10 External links
A wallmount cabinet containing
optical fiber interconnects. The
yellow cables are single mode fibersÍž
the orange and aqua cables are multi
mode fibers: 50/125 µm OM2 and
50/125 µm OM3 fibers respectively.
History
Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel
Colladon and Jacques Babinet in Paris in the early 1840s. John Tyndall included a demonstration of it in his public
lectures in London, 12 years later.[9] Tyndall also wrote about the property of total internal reflection in an
introductory book about the nature of light in 1870:
When the light passes from air into water, the refracted ray is bent towards the perpendicular... When
the ray passes from water to air it is bent from the perpendicular... If the angle which the ray in water
encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the
water at all: it will be totally reflected at the surface.... The angle which marks the limit where total
reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint
glass it is 38°41′, while for diamond it is 23°42′.[10][11]
Unpigmented human hairs have also been shown to act as an optical fiber.[12]
Practical applications, such as close internal illumination during dentistry, appeared early in the twentieth century.
Image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell
and the television pioneer John Logie Baird in the 1920s. The principle was first used for internal medical
examinations by Heinrich Lamm in the following decade. Modern optical fibers, where the glass fiber is coated
with a transparent cladding to offer a more suitable refractive index, appeared later in the decade.[9] Development
https://en.wikipedia.org/wiki/Optical_fiber
2/22
Optical fiber Wikipedia, the free encyclopedia
Optical fiber
From Wikipedia, the free encyclopedia
An optical fiber (or optical fibre) is a flexible, transparent fiber made by
drawing glass (silica) or plastic to a diameter slightly thicker than that of a
human hair.[1] Optical fibers are used most often as a means to transmit
light between the two ends of the fiber and find wide usage in fiberoptic
communications, where they permit transmission over longer distances and
at higher bandwidths (data rates) than wire cables. Fibers are used instead
of metal wires because signals travel along them with lesser amounts of
lossÍž in addition, fibers are also immune to electromagnetic interference, a
problem from which metal wires suffer excessively.[2][3] Fibers are also
used for illumination, and are wrapped in bundles so that they may be used
to carry images, thus allowing viewing in confined spaces, as in the case of
a fiberscope.[4] Specially designed fibers are also used for a variety of other
applications, some of them being fiber optic sensors and fiber lasers.[5]
Optical fibers typically include a transparent core surrounded by a
transparent cladding material with a lower index of refraction. Light is kept
in the core by the phenomenon of total internal reflection which causes the
fiber to act as a waveguide.[6] Fibers that support many propagation paths
or transverse modes are called multimode fibers (MMF), while those that
support a single mode are called singlemode fibers (SMF). Multimode
fibers generally have a wider core diameter and are used for shortdistance
communication links and for applications where high power must be
transmitted. Singlemode fibers are used for most communication links
longer than 1,000 meters (3,300 ft).
An important aspect of a fiber optic communication is that of extension of
the fiber optic cables such that the losses brought about by joining two
different cables is kept to a minimum.[7] Joining lengths of optical fiber
often proves to be more complex than joining electrical wire or cable and
involves careful cleaving of the fibers, perfect alignment of the fiber cores,
and the splicing of these aligned fiber cores. For applications that demand a
permanent connection a mechanical splice which holds the ends of the
fibers together mechanically could be used or a fusion splice that uses heat
to fuse the ends of the fibers together could be used. Temporary or semi
permanent connections are made by means of specialized optical fiber
connectors.[8]
A bundle of optical fibers
Fiber crew installing a 432count
fiber cable underneath the streets of
Midtown Manhattan, New York City
The field of applied science and engineering concerned with the design and
application of optical fibers is known as fiber optics.
Contents
A TOSLINK fiber optic audio cable
with red light being shone in one end
transmits the light to the other end
1 History
2 Uses
2.1 Communication
https://en.wikipedia.org/wiki/Optical_fiber
1/22
7/14/2016
Optical fiber Wikipedia, the free encyclopedia
2.1 Communication
2.2 Sensors
2.3 Power transmission
2.4 Other uses
3 Principle of operation
3.1 Index of refraction
3.2 Total internal reflection
3.3 Multimode fiber
3.4 Singlemode fiber
3.5 Specialpurpose fiber
4 Mechanisms of attenuation
4.1 Light scattering
4.2 UVVisIR absorption
5 Manufacturing
5.1 Materials
5.2 Process
5.3 Coatings
6 Practical issues
6.1 Cable construction
6.2 Termination and splicing
6.3 Freespace coupling
6.4 Fiber fuse
6.5 Chromatic dispersion
7 See also
8 References
9 Further reading
10 External links
A wallmount cabinet containing
optical fiber interconnects. The
yellow cables are single mode fibersÍž
the orange and aqua cables are multi
mode fibers: 50/125 µm OM2 and
50/125 µm OM3 fibers respectively.
History
Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel
Colladon and Jacques Babinet in Paris in the early 1840s. John Tyndall included a demonstration of it in his public
lectures in London, 12 years later.[9] Tyndall also wrote about the property of total internal reflection in an
introductory book about the nature of light in 1870:
When the light passes from air into water, the refracted ray is bent towards the perpendicular... When
the ray passes from water to air it is bent from the perpendicular... If the angle which the ray in water
encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the
water at all: it will be totally reflected at the surface.... The angle which marks the limit where total
reflection begins is called the limiting angle of the medium. For water this angle is 48°27′, for flint
glass it is 38°41′, while for diamond it is 23°42′.[10][11]
Unpigmented human hairs have also been shown to act as an optical fiber.[12]
Practical applications, such as close internal illumination during dentistry, appeared early in the twentieth century.
Image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell
and the television pioneer John Logie Baird in the 1920s. The principle was first used for internal medical
examinations by Heinrich Lamm in the following decade. Modern optical fibers, where the glass fiber is coated
with a transparent cladding to offer a more suitable refractive index, appeared later in the decade.[9] Development
https://en.wikipedia.org/wiki/Optical_fiber
2/22
