Nonlinear Frequency-Division Multiplexing in the Focusing Regime
  Achievable rates of the nonlinear frequency-division multiplexing (NFDM) and wavelength-division multiplexing (WDM) subject to the same power and bandwidth constraints are computed as a function of transmit power in the standard single-mode fiber. NFDM achieves higher rates than WDM. 
Xianhe Yangzhang, Mansoor I. Yousefi, Alex Alvarado, Domanic Lavery,   Polina Bayvel
cs.IT math.IT