Modelling of transmission nonlinearities and fibre parameter optimisation in dense WDM systems with optical amplifiers

Upgrading standard fibre (CSMF) using dispersion correcting fibre (DCF) is an attractively simple and low cost method of breaching dispersion-limited transmission distances. The DCF is designed such that it has high, negative chromatic dispersion and with an appropriate length can compensate for the dispersion which has accumulated in standard fibre at a particular wavelength. A number of alternative dispersion-management schemes have been proposed and demonstrated for future high bit-rate fibre networks but in the main these works have concentrated on either CSMF as the compensator for lengths of dispersion shifted fibre (DSF) or by sections of DSF with alternating dispersion sign. We present simulation results that highlight the improvement of transmission distance by positioning the compensator at the beginning of each span and how the three Kerr nonlinearities, self-phase modulation (SPM), cross-phase modulation (CPM) and four-wave mixing (FWM), are suppressed by the to two important DCF parameters: dispersion and loss