In the optical
fibers, the lightwaves (signals) are guided with a minimum attenuation.
???. Light.sources.and.light.detectors: At both ends of an optical transmission system,
light sources and light detectors are found. At the transmitting-end, the light source
(light emitter) modulates electrical signals into light pulses. The opposite process, that
is, to modulate light pulses into electrical signals, is performed by the light detectors
at the receiving-end.
??? Optical Amplifiers: To amplify an attenuated optical signal, unlike the conventional
repeaters that perform respectively optical-electrical conversion, electrical amplification,
and then electrical-optical conversion, the optical amplifiers operate completely
in the optical domain. The optical amplifiers can boost the power levels of the optical
signals. Amplifiers can be classified to two fundamental amplifier types: Semiconductor
Optical Amplifiers (SOAs) and Doped-Fiber Amplifiers (DFAs).
???. Multiplexers.and.De-multiplexers:.Multiplexers and De-multiplexers are essential
components in the optical transmission systems. Multiplexers converge and combine
multiple incoming signals into one beam. The de-multiplexers have the ability to
Abdelouahab, Abbou, Tat, & Ta b
Copyright ?© 2007, Idea Group Inc.
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