Nonlinearity-tolerant time domain hybrid modulation for 4–8 bits/symbol based on 2A8PSK

We propose time domain hybrid modulation to cover 4-8 bits/symbol range, based on 5, 6, and 7 bits/symbol 4D-2A8PSK. Simulation results indicate that they have up to 1.6 dB higher span loss budget than the hybrid modulation based on conventional modulation formats in nonlinear channels.