Nonlinear penalty suppression in cascades of optical add-drop multiplexers

Through an extensive simulation study, it is shown for the first time that the presence of optical add-drop multiplexers (OADMs), and in particular the optical filtering associated with them, improves the overall performance of systems suffering by nonlinear effects. This is due to that periodic optical filtering assists in suppressing the spectral broadening imposed by the Kerr nonlinearity and, therefore, suppresses the associated penalty. Our results identified optimum operating regimes, in terms of launch power and OADM filter bandwidths, for OADM-chain wavelength-division-multiplexing systems.