الفهرس 
General IntroductionOnly 14 pages are availabe for public view
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Abstract
In this thesis, a hybrid optical amplifier is recommended including an Er3+ Yb3+ codoped fiber amplifier (EYCDFA) as a pre amplifier and a Raman fiber amplifier (RA) as a post amplifier. The performance characteristics of the hybrid amplifier (HA) are theoretically studied including gain (G), noise figure (NF), gain bandwidth and Gain Variation Ratio (GVR). The performance of the suggested HA has been studied and compared with EYDFA only amplifier for similar system specifications. Furthermore, a comparative study of different types of glasses (phosphate and silica glass) is also performed.The effects of varying various parameters, like Er/Yb and Raman pump power, Er/Yb and Raman amplifier length, Er3+ and Yb3+ concentrations and input signal power on gain and noise figure are investigated in case of HA and EYDFA only. The gain and noise figure are calculated at steady state conditions, the initial energy transfer efficiency for EYDFA is introduced, while the Amplified Spontaneous Emission (ASE) noise is neglected, at 1 m length of EYDFA, 25 km Raman amplifier length, 6 𝗑 1026 m-3 Yb concentration, 5 𝗑 1025 m-3 Er concentration, and input signal power of 0 dBm in the signal wavelength range (1500 – 1600 nm).