Nonlinear Fourier transform based optical communication systems with FBMC wave-carriers.

The nonlinear Fourier transforms (NFT) transmission scheme continues to show a lot of potential in the field of optical communications. Nonlinear frequency division multiplexing (NFDM), which is based on the NFT concept, has been shown to offer immunity against Kerr nonlinearity and dispersion in optical fiber transmission systems. However, some issues such as relatively low achievable information rate (AIR) and the interaction of the optical signal with the inline amplifier noise still constitute a major setback for NFT-based schemes.

Channel model and the achievable information rates of the optical nonlinear frequency division-multiplexed systems employing continuous b-modulation.

Following the rise in interest in transmission systems employing the nonlinear Fourier transform (NFT) for the nonlinearity mitigation, we present the theoretical analysis of the achievable information rates in these systems, addressing the case of continuous b-modulated systems. Using adiabatic perturbation theory and the asymptotic analysis by means of Riemann-Hilbert problem, we obtain a remarkably simple input-output relation for arbitrary b-modulated transmission. Based on this model, we estimated the spectral efficiency for various single polarization (scaled and unscaled) b-modulated systems and observed an excellent agreement between our theory and the numerical results in the regime when the inline amplifier noise is the dominant source of spectral distortion.