الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Communication system revolution, especially optical communication needs power fundamentals to enable the extremely high data rates and huge length spans. This huge length span needs signal power enough to reach the receiver end with a reasonable signal to noise ratio to be decoded. The long spans optical links can be powered by the regenerators or optical amplifiers. but, the optical amplifiers compared to the regenerators are the revolution pass key as the regenerators are time consumer as transform the optical to electrical then after amplification transform to optical again, the optical amplifiers amplify the signal in its optical form. Raman amplifier is the revolution master as it amplifies during the transmission on the transmission media which mean no additional amplification equipment also, it has a very high gain and low signal to noise ratio.
Raman amplifier need to be enhanced to meet the optical communication systems demands which will enable the ultra-long haul communication systems. This enhancement is summarized in the gain increasing, bandwidth broadening and enhance the noise figure. In 2010, Raman gain for backward pumping using three different fiber types investigated by Nihal M. Anwar and Mostafa H. Aly. The rate and propagation differential equations characterizing fiber Raman amplifiers (FRAs) are numerically solved. In this way, the gain is simulated for the given FRA parameters or the required fiber parameters and signal/pump power values could be optimized for a desired FRA gain. Gain is obtained as a function of fiber length and pump power. According to the obtained results, gain is strongly dependent on the fiber length and pumping power.