Demonstration of Fully Nonlinear Spectrum Modulated System in the Highly   Nonlinear Optical Transmission Regime
  We report a 3 dB increase in the nonlinear threshold of a 64*0.5Gbaud 16-QAM continuous-nonlinear-spectrum modulated signal by nonlinear multiplexing with QPSK modulated multi-solitons, showing the first ever fully nonlinear-spectrum modulated system in the highly nonlinear regime. 
Vahid Aref, Son T. Le, Henning Buelow
cs.IT math.IT