CD Estimation in FMFs Using the Auto-Correlation of the Signal Power Waveform

The exhaustion of the capacity of conventional optical systems based on standard single-mode fibers (SSMF) requires new solutions cope with the exponential traffic increase. In this scenario, transmission by few-mode fibers (FMFs) appears as a strong candidate. These systems require adaptive digital signal processing (DSP) algorithms with multiple inputs and multiple outputs (MIMO) at the receiver in order to recover the signals multiplexed in the various spatial and polarization modes. However, proper functioning of these equalizers requires the pre-compensation of chromatic dispersion (CD) in the receiver using static filters. Since the DSP algorithms in mode-multiplexed systems have a slow convergence, the typical scanning algorithms become difficult to apply. In this work, we investigate the applicability of an algorithm based on the auto-correlation of the signal power waveform to estimate the CD in FMF systems. The results indicate an algorithm vulnerability with the increase of the inter-mode crosstalk level.