الفهرس 
CHAPTER 1Only 14 pages are availabe for public view
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Abstract
The decisive measure of the worth of any communications medium is its transmission
performance, which at the most fundamental level is measured by the signal loss through a
finite length of a channel, and the bandwidth limiting effects which constrain the capacity
of the channel. The solution of these problems is direct optical amplification. Nonlinearity
effects arose as optical fiber data rates, transmission lengths, number of wavelengths, and
optical power levels increased.
Optical amplifiers have a strong effect on the performance and design of optical
networks resulting in the deployment of a large number of high capacity long distance
optical transmission systems. In fact, the finest amplification span length is one that
facilitates the best trade-off between low cost requirements - a low number of amplifiers,
ensuring cost efficiency- and stringent system performance constraints - a large number of
amplifiers ensuring good performance of transmission system because of the reduction of
accumulated amplified spontaneous emission (ASE) noise.