Scanning-Based Chromatic Dispersion Estimation in Mode-Multiplexed Optical Systems

Mode-multiplexed coherent optical systems emerge as an alternative to overcome the capacity limits of current optical communication systems. As in single-mode systems, mode-multiplexed transmission experiences accumulated chromatic dispersion that must be estimated and compensated for by digital signal processing. Although scanning-based methods are widely used to estimate chromatic dispersion in single-mode optical systems, their performance in mode-multiplexed systems has not been evaluated. In this paper, we study three scanning-based chromatic dispersion estimation techniques in the scope of mode-multiplexed optical systems. The results indicate that the algorithms loose accuracy for high levels of crosstalk and ASE noise. However, we show that the estimation criterion based on the delay-tap sampling method can be properly modified to significantly improve the estimation performance even in the worst scenario of crosstalk evaluated.