Advanced digital signal processing for coherent and non-coherent optical transmission

Digital signal processors (DSP) are recently introduced in coherent long-haul optical transmission systems as well as in non-coherent access networks. This contribution reviews a number of specific signal processing algorithms that are useful in such systems. We focus on advanced equalisers for linear and nonlinear distortions. We examine the Tomlinson-Harashima precoding approach as well as advanced flexible non-integer fractionally-spaced butterfly equalisers. For nonlinearity compensation Volterra based equalization is investigated.