Modelling the transmission of a 40-Gbit s-1 NRZ-ADPSK signal in 50-GHz networks

We study numerically the effect of linear and nonlinear distortions on the transmission of a 40-Gbit s^-1 NRZ-ADPSK signal. The results of the numerical simulation coincide within the measurement accuracy with the experimental data, which indicates the adequacy of the mathematical model of the communication line, transmitter and receiver. We have found experimentally and numerically that in communication systems based on a standard telecommunication fibre negative dispersion (approximately –160 ps nm^-1) introduced into the signal being transmitted provides an increase in the maximum admissible signal power coupled into a span and in the value of the admissible attenuation of the spans at 2 dB. It is established that nonlinear distortions caused by the presence of adjacent channels in a frequency network with a step of 50 and 100 GHz (crosstalks) are insignificant in comparison with the interchannel nonlinear distortions.