A multilevel coded modulation (MLCM) system in the presence of nonlinear phase noise for fiber optical communication is introduced. The proposed scheme exploits a 16-point ring constellation with nonlinear post compensation of the self phase modulation produced via the Kerr effect. A new set partitioning based on the Ungerboeck approach is introduced to maintain unequal error protection in amplitude and phase direction. The rate allocation for the MLCM component codes for different fiber lengths and transmit powers are done numerically. Simulation results show that the proposed MLCM system provides up to 2 dB gain over a forward error correcting scheme for a block error rates around 10^{-9}, with the same overhead (7%) and complexity.
['Lotfollah Beygi', 'Erik Agrell', 'Pontus Johannisson', 'Magnus Karlsson']
A Novel Multilevel Coded Modulation Scheme for Fiber Optical Channel with Nonlinear Phase Noise