Experimentelle Untersuchung adaptiver flexibler digitaler Signalverarbeitung für hybride Modulationsformate

In today’s world, the Internet has become an indispensable part of almost every aspect of life. In the private sector, more and more Internet-enabled mobile devices such as laptops, cell phones or tablets are being used. In the last few years, the daily way of life has changed. What a decade ago was still determined by analog television is today influenced by digital media. In addition to the requirements of mobile radio, the demands on the optical transmission systems behind it are growing in equal measure. Multi-stage modulation formats such as polarization multiplexing or quadrature amplitude modulation are already increasingly being used in optical transmissions. When considering ways to increase transmission rates, greater attention must be paid to linear and nonlinear interference as well as interference from imperfect components in optical systems. These limiting effects are given special attention in this thesis. The focus of this work is on the one hand on increasing the channel rate by modern digital signal processing and on the other hand on high-quality modulation formats in different optical transmission systems. In addition, this thesis discusses the possibility to design the data rate adaptively under given transmission conditions in dual polarization networks with wavelength division multiplexing. This is a prerequisite for supporting modern concepts determined by software. The goal of the research activity on which this work is based is to be able to design the data rate adaptively in coherent wavelength division multiplexing networks with a dense grid of less than 50 GHz. The main focus is on the investigation, optimization and experimental implementation of hybrid modulation and its digital signal processing in transmitter and receiver. Among other concepts, hybrid modulation offers a central abstraction possibility by allowing the individual data streams to be modulated independently of each other. Furthermore, this thesis shows that already common concepts of digital signal processing are applicable to hybrid modulation. The developed concept was realized by a WDM scenario with a channel spacing of 37.5 GHz and investigated in simulations and experiments. A numerical model for the investigation of glass fibers under birefringence was realized with the implementation and optimization of the solution to the Manakov-PMD equation by the split-step method. This work also performs important aspects of general digital signal processing.