Methods of nonlinear fourier-based optical transmission with periodically-extended signals

The nonlinear Fourier transform (NFT) has attracted great interest recently as a new technique for nonlinearity mitigation in fibre-optic transmission. Most of the attention has so far been paid to the NFT for time-decaying signals while periodic signals can potentially ameliorate some difficulties of conventional NFT, offering a better system performance. We consider two communication systems based on the usage of periodic NFT (PNFT): with signal processing based (i) on the reduced algebro-geometric and (ii) on Riemann-Hilbert problem (RHP) approaches. Simulation results show that both methods can be used for nonlinearity mitigation. However, the latter approach is expandable without considerable penalty in processing complexity, which makes it a more appealing option for implementation.