  In this thesis the creation of nonlinear interference noise (NLIN) in the
context of impairment aware flexible optical networks is investigated to
estimate transmission quality. In particular, the nonlinear interference of
neighboring channels (interferer) during transmission on a channel under test
is studied. The modulation format of the interferer, the accumulated chromatic
dispersion of the interferer, the span length and channel spacing are
identified as the parameter influencing the generation of NLIN in the context
of flexible optical networks. Estimation of the NLIN is done based on the
evaluation of numerical simulation results and compared to recent analytical
transmission models, namely the Gaussian noise model and the enhanced Gaussian
noise model. In addition to nonlinear noise power, the simulations also yield
information about the phase- and circular-noise contributions as well as the
correlation time of the phase noise. The results are evaluated in the context
of the pulse-collision picture and the influence on transmission quality is
discussed.
