Seimetz, M.M.Seimetz2022-03-042022-03-042009https://publica.fraunhofer.de/handle/publica/22087910.1007/978-3-540-93771-5_6During fiber transmission, optical signals are distorted by several linear and nonlinear degradation effects. This chapter provides a brief description of the most important fiber degradation effects such as fiber attenuation, chromatic dispersion, Kerr nonlinearities, nonlinear scattering effects, polarization mode dispersion and nonlinear phase noise, laying the foundations for understanding the specific behavior of high-order modulation formats in relation to various transmission impairments, discussed in detail later on in Chap. 7 and Chap. 8.en621book article