(2022) Efinger, Daniel; Speidel, Joachim (Prof. Dr.-Ing.)
This thesis addresses electronic equalization of intersymbol interference caused by chromatic and polarization mode dispersion in intensity-modulated optical communication links with direct detection. The simple and cost-efficient system setup is, even at high bit rates of 40 Gbit/s and beyond, of interest for short-haul optical links in metropolitan, aggregation or local area networks. Therefore, this thesis investigates preferably simple and low-complexity equalizer structures, which are able to compensate well for the nonlinear characteristics and influences of the intensity-modulated optical communication link with direct detection. Starting with system modeling and the introduction to different equalization methods, we identify low-complexity feed-forward and decision-feedback equalizers in the first part of this thesis. We further put their chromatic and polarization mode dispersion compensation performance to the broader context by comparison to maximum likelihood sequence estimation. Finally, we come to the investigation of adaptation algorithms for equalizer coefficient adjustment, which accounts for the time-variant nature of polarization mode dispersion, while still targeting preferably simple and efficient realization.
