Polarization-Division Multiplexing Based on the Nonlinear Fourier Transform

TL;DR

This paper extends the nonlinear Fourier transform (NFT) to polarization-division multiplexing in optical fibers, demonstrating improved performance and robustness against polarization-mode dispersion, with potential applications in space-division multiplexing.

Contribution

It generalizes NFT algorithms from scalar to vector form for dual polarizations and compares PDM-NFDM with PDM-OFDM, showing significant Q-factor improvements.

Findings

PDM-NFDM achieves a 6.4 dB higher Q-factor than PDM-OFDM.

Performance of PDM-NFDM is comparable to single polarization NFDM at doubled data rate.

Polarization-mode dispersion does not significantly degrade PDM-NFDM performance.

Abstract

Polarization-division multiplexed (PDM) transmission based on the nonlinear Fourier transform (NFT) is proposed for optical fiber communication. The NFT algorithms are generalized from the scalar nonlinear Schr\"odinger equation for one polarization to the Manakov system for two polarizations. The transmission performance of the PDM nonlinear frequency-division multiplexing (NFDM) and PDM orthogonal frequency-division multiplexing (OFDM) are determined. It is shown that the transmission performance in terms of Q-factor is approximately the same in PDM-NFDM and single polarization NFDM at twice the data rate and that the polarization-mode dispersion does not seriously degrade system performance. Compared with PDM-OFDM, PDM-NFDM achieves a Q-factor gain of 6.4 dB. The theory can be generalized to multi-mode fibers in the strong coupling regime, paving the way for the application of the NFT to address the nonlinear effects in space-division multiplexing.