Analyse comparative des performances des systèmes WDM avec compensation de dispersion pour des transmissions longue distance à 8×10 Gbps et 8×20 Gbps en modulation NRZ

Abstract

This thesis focuses on improving the performance of high-speed optical transmissions in the presence of chromatic dispersion. It begins with a detailed presentation of optical fibers, their types, physical properties, limitations, and applications, as well as the key components of an optical transmission system (transmitters, modulators, amplifiers, receivers, WDM). The second chapter addresses dispersion phenomena and compensation techniques, particularly dispersion compensating fibers (DCF) and fiber Bragg gratings (FBG), emphasizing the different types and working mechanisms of FBGs. The third chapter is based on simulations using OptiSystem, comparing various compensation schemes (pre, post, symmetric) in both single-channel and WDM configurations. Results show that symmetric DCF–FBG compensation offers the best performance (high Q-factor, low BER) even at 20 Gbps over long distances. The study highlights the value of a hybrid approach to overcome the limitations of traditional techniques, paving the way for more reliable and efficient optical transmissions for future networks.