الفهرس 
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Abstract
Optical fiber is one of the most important communication media in communication systems due to its characteristics compared to other communication channels. Dense Wavelength Division Multiplexing (DWDM) is the most effective utilization technology used in optical fiber communication systems. It can increase the capacity and meet the bandwidth requirement by combining some signals which having various wavelengths on a particular fiber cable then transmit them all at the same time. The main factors that affect DWDM optical networks are attenuation, non-linearity and dispersion. Dispersion affects the most and it is rough to overcome that one as related to other. The main goal of this thesis is to compensate chromatic Dispersion (CD). chromatic Dispersion Compensation (CDC) using Fiber Bragg Grating (FBG) techniques in WDM and DWDM systems is presented in this thesis. A suggested WDM system for 10 Gbps using Chirped Fiber Bragg Grating (CFBG) as a dispersion compensator, Non-Return-to-Zero (NRZ) modulation format and an Erbium Doped fiber Amplifier (EDFA) on a Single Mode Fiber (SMF) is designed. The result shows that, with using uniform apodized linear CFBG grating length of 90mm, SMF length of 30 Km, input power of 15 dBm and attenuation coefficient 0.1 dB/Km, the Quality-Factor (QF) is 39.9373 dB. However, increasing SMF length to 100 Km, the QF is 12.173 dB. Apodization and chirping functions can also add useful features to CFBG, enhancing the dispersion compensation performance. They offer significantly improved side-lobe suppression so, we introduced a system with different apodization and chirping functions. It can be observed that uniform apodized quadratic CFBG is the best technique for dispersion compensation. So, we applied this technique in the previous four channel WDM and DWDM system at wavelengths (1550,1551,1552 and 1553 nm), The result shows that, with using CFBG grating length of 7mm, SMF length of 30 Km, the QF is (55.135 dB in WDM) and (62.751 dB in DWDM). However, increasing SMF length to 100 Km, the QF is (11.2104 dB in WDM) and (11.701 dB in DWDM). Thus, Results show that this model is more efficient in terms of QF, Bit Error Rate (BER) and eye diagrams related to other published papers which can be useful in many applications in telecommunication system like Sensor Networks, Remote Radar Networks, Tele-spectroscopic process control network, and many more networks.