Improvement of the performance of high-capacity WDM-transmission systems due to nonlinear optical effects

Abstract

The impact of nonlinear optical effects, the optimization of the dispersion, the bandwidth of the filters and the optical signal powers play a major role in an optical network and even more the higher the data rates are. This work deals with the simulation of dispersion in order to determine its impact on the performance of high-capacity WDM-transmission systems. By consideration of nonlinear optical effects and suitable dispersion management, it is shown that the system performance can partly be improved. A 10 Gbps or 40 Gbps external modulated laser signal is transmitted through a standard single mode fiber (SSMF) followed by a dispersion compensation fiber (DCF) (postcompensation). Due to cross-phase modulation, four-wave mixing and self-phase modulation crosstalk which influences the optimum length of the DCF can be detected. The filter bandwidth and length of the DCF have been optimized for various signal powers and two different data-rates. It turned out that the influence of different non-linear effects on the system performance can be partly reduced by optimized dispersion management (undercompensation). It is shown that the optimum length of the DCF is independent of the signal bandwidth. The simulation reasons the maximum launched power per channel and the optimum filter bandwidth for 40 Gbps transmission systems. Real measurements on optical components and networks agree with our simulation results.