Marco SECONDINI  (Scuola Superiore Sant’Anna)

To NFT, or not to NFT, different ways of dealing with fiber nonlinearity

Abstract
Fiber nonlinearity limits the performance of current optical fiber communication systems. In this talk, we review different approaches that can be followed to mitigate the impact of fiber nonlinearity. In particular, we focus on the idea that fiber nonlinearity can be avoided, or at least reduced, by properly shaping the waveforms that are transmitted through the optical fiber. To this aim, we consider two rather different approaches, namely, constellation shaping and nonlinear frequency division multiplexing. The former acts at a symbol level, optimizing the constellation in a high-dimensional space to minimize fiber nonlinearity. The latter acts at a waveform level, using the nonlinear Fourier transform to perform modulation and demodulation in the nonlinear spectrum domain, where fiber propagation is linear. Pros and cons of the two techniques are discussed, exploring their potential and limits.