# Observing the Effect of Polarization Mode Dispersion on Nonlinear Interference Generation in Wide-Band Optical Links

## TL;DR

This paper investigates how polarization mode dispersion affects nonlinear interference in wide-band optical links, demonstrating through simulations that the Manakov equation remains valid for modeling NLI even with significant PMD over broad bandwidths.

## Contribution

The study provides numerical evidence that the Manakov equation can accurately model nonlinear interference in wide-band systems despite the presence of polarization mode dispersion.

## Key findings

- PMD has negligible impact on NLI generation across bandwidths.
- The Manakov equation remains valid beyond its traditional bandwidth limit.
- Numerical simulations confirm the robustness of NLI modeling with PMD effects.

## Abstract

With the extension of the spectral exploitation of optical fibers beyond the C-band, accurate modeling and simulation of nonlinear interference (NLI) generation is of the utmost performance. Models and numerical simulation tools rely on the widely used Manakov equation (ME): however, this approach when considering also the effect of polarization mode dispersion (PMD) is formally valid only over a narrow optical bandwidth. In order to analyze the range of validity of the ME and its applicability to future wide-band systems, we present numerical simulations, showing the interplay between NLI generation and PMD over long dispersion-uncompensated optical links, using coherent polarization division multiplexing (PDM) quadrature amplitude modulation (QAM) formats. Using a Monte-Carlo analysis of different PMD realizations based on the coupled nonlinear Schr\"{o}dinger equations, we show that PMD has a negligible effect on NLI generation, independently from the total system bandwidth. Based on this, we give strong numerical evidence that the ME can be safely used to estimate NLI generation well beyond its bandwidth of validity that is limited to the PMD coherence bandwidth.