Smart modulation strategies for dispersion control in optical WDM superchannel systems: a comprehensive review

Abstract The increasing need for data-hungry applications has further hastened the pace of evolution for optical communication systems to move toward wavelength division multiplexing (WDM) superchannel-based architectures. Even though superchannel-based optical communication systems have the capability to achieve terabit per second transmission rates with high spectral efficiencies, large bandwidth and higher symbol rate of superchannels have further intensified the effects of fiber dispersions. This review aims to offer a comprehensive review of intelligent modulation techniques for effective management of dispersions in optical WDM superchannel-based systems. The major effects of dispersions have been discussed, followed by a review of evolutionary path for optical modulation formats with increasing awareness of dispersions. The major emphasis is given to co-design methods involving modulation and digital signal processing. In addition, comparative assessment of various parameters also reveals the trade-offs that exist between dispersion tolerance, spectral efficiency, and OSNR requirements. In addition, some of open challenges and emerging areas of research are also discussed in relation to optimization of modulation and DSP using adaptive and machine learning approaches in the context of EONs. The insights that are provided are aimed at providing guidelines for the future of dispersion-aware modulation and DSP approaches for high-capacity optical superchannel systems.