10.18453/rosdok_id00002662 Eichelkraut, Toni Toni Eichelkraut http://d-nb.info/gnd/1209498219 Universität Rostock 2018 530 Physics 2018 en http://purl.uni-rostock.de/rosdok/id00002662 urn:nbn:de:gbv:28-rosdok_id00002662-2 This thesis aims at laying the foundation for handling parity-time-symmetric structures in femtosecond-LASER-written waveguide arrays. This is done by presenting a thorough theoretical and experimental investigation of sinusoidally modulated waveguides. In addition, this thesis comprises the first experimental realization of a parity-time-symmetric structure on this platform, as well as an extended coupled mode theory for dissipative waveguides. In this context, the existence of diffusion in ordered parity-time-symmetric systems is discussed.