Characterization of Nonlinear Fiber Interactions Using Multidimensional Mutual Information Over Time and Polarization

Achievable information rates are experimentally investigated in coherent fiber optical communication for different demappers by using two-dimensional and four-dimensional estimates of the channel statistics. Polarization-multiplexed 16-ary quadrature amplitude modulation with symbol rates of either 10 Gbaud or 20 Gbaud is investigated in experiments over links with either erbium-doped fiber amplification or Raman amplification. We show that performing demapping over two consecutive time slots rather than two orthogonal polarization states can be beneficial, and both cases show gains over conventional two-dimensional demappers.