Link design concept using equalization techniques for robust optical transparent long haul transmission

摘要

In this work we investigate the influence of adaptive equalization techniques on the link design of long haul optical transparent transmission (up to 800 or 1600 km). Receiver-side electronic and optical equalizers can be utilized to mitigate all kinds of distortions generated in the transmission link e.g. by the fiber, amplifiers or other network elements (OADMs, OXCs) making the systems robust and more tolerant against these effects. However, the performance of the realizable equalizers might not be sufficient to compensate for all dispersion of a link in optical transparent core and long haul networks which are typically in the range of up to 1600 km. Therefore we present a link design concept which takes a distributed static dispersion compensation as well as adaptive equalization at link termination points (e.g. OADMs or final receivers) into account. In our concept only a coarse compensation with DCF-x modules which compensate only for e.g. 80, 20 or 5 km standard single mode fiber is used and the residual dispersion will be handled by an adaptive equalizer. The system behavior is analyzed for specific target lengths of 800 and 1600 km taking chromatic dispersion, nonlinear effects and amplifier noise into account. It is shown how the deployment of receiver-side equalizers may be used to allow for a coarse DCF granularity while maintaining the same overall system performance. Several amplitude modulation formats like NRZ, RZ or duo-binary are investigated within this concept.