Algoritmos de Equalização da Dispersão Cromática em Sistemas de Comunicações Ópticas Coerentes

João Luís Filipe Santos

Key information

Authors:

João Luís Filipe Santos (João Luís Filipe Santos)

Supervisors:

João Emanuel Fernandes Monteiro; Paulo Sérgio De Brito André (Paulo Sérgio De Brito André)

Published in

05/18/2016

Abstract

In order to respond to the technologic society expectations and satisfying the nowadays search of services who required a high spectral efficiency, emerge an interest about coherent optical systems, that allows multi-level modulation formats and digital signal processing. So, the study of performance of equalization algorithms at digital domain is essential in order to get the best solutions. At this dissertation, a coherent optical communication system was developed using the MATLAB/SIMULINK programing to study chromatic dispersion equalization of the optical fiber and to estimate the signal-to-noise ratio along this process in order to rate his quality. At first, the equalization of fixed chromatic dispersion was studied by Overlap-Save algorithm and then was studied the equalization of residual chromatic dispersion (resulting from the variation of fiber dispersion parameter due to thermal variations) by the LMS algorithm. Regarding this algorithm was studied his conventional implementation, were are only used previous symbols to the symbol being equalized, and also was studied the availability of being used, additionally, later symbols. At this context, was demonstrate that the equalization by Overlap-Save algorithm allows an excellent equalization of fixed chromatic dispersion and that the LMS algorithm, using previous and later symbols, due to residual chromatic dispersion, allows better results comparing with the study were are only used previous symbols.