Download FIBER-OPTIC COMMUNICATION LINKS –ACTIVE AND PASSIVE

FIBER-OPTIC COMMUNICATION LINKS –ACTIVE AND PASSIVE ELEMENTS
ZHETPISBAVA A.T., ZHUNUSOV K.X.
e-mail:[email protected]
Fiber-optic communication links – are links that include active and passive elements,
which are able to transmit light flow through fibers.
Fiber - optic links enable to create separate networks and connect several existing
networks into the one. There are two methods are used for connecting networks: physical ( via an
optical fiber ) and logical (via data transfer protocols ). These days, optical fiber communication
is recognized as the most perfect medium for data transmition. The level of modern civilization
determined by the volume of transferred and processed information. Acording to the theoretical
and statistical research works, the amount of transmitted information increases with the square of
GDP growth , moreover, the real demand consistently exceeds the predicted one . The rapid
development of telecommunication technology and the use of optical transmission techniques
also have affects on equipment of Closed Circuit Television (CCTV).
The most important advantages of fiber – optic communication links are listed below:
 Low transmission loss
Fiber-optic cables transmit image signals with small losses over distances of hundreds of
kilometres without signal regeneration. It is very convenient for arranging videos at areal
objects and objects with spread structure.
Lack of frequency distortion of video signals.
Optical communication methods provide undistorted transmission of the entire spectrum
of video signals, which provides the desired resolution and eliminates the need for
different frequency offsets.
 Broadband link
The broad band of transmission signals in an optical fiber enables to transmit several
video signals on the same cable and at the same time, and to achieve bidirectional
transmission of video, audio, data, etc.
 Resistance to interference and disruption
Fiber optic cable is absolutely insensitivity to the external electrical interference and
disruption, which ensures stable operation of information transmission system in a
complex electromagnetic environment, which is recognised in industrial facilities.
 Electrical isolation
Due to the fact that optical signals not require grounding, source and video sink are isolated from
each other; therefore there is no problems associated
with the organization and alignment of the contour and the grounding potential. The lack
of grounding problems in the transmission of video signals and protection from sparks
and fire makes fiber optic cables the most appropriate cables for use in surveillance
systems, which requires to follow explosion and fire safety rules.
The main disadvantages of fiber-optic communication lines are:
 radiation exposure to fibers, which results in dimmer spots and increase of damping;
 hydrogen attack of glass, leading to microcracks in the fiber and deterioration of its
effetcs.
 the high cost of both the equipment and works on terminations and splices.
 difficulties associated with the use of specific equipment (optical crosses, couplings, etc.)
necessary for routing video information.
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 REFERENCES
[1] Kemelbekov B. Zh. , Myshkin V.F., Han V.A., Optic Cables, (2001), izdatelstvo nauchno-tehnicheskoi
literatury, Tomsk polytechnic university, Tomsk, 352p.