Implication of Parameter Values on Low-Pass Filter Assisted Digital Back Propagation for DP 16-QAM

The low-pass filter (LPF) assisted digital back propagation (DBP) algorithm is investigated for 112 Gb/s dual-polarization 16-ary quadrature-amplitude-modulation transmission up to 2400 km. The performance implications of the parameter values for the LPF-DBP algorithm are considered in detail through determining the dependence of the bit error ratio (BER) on the number of nonlinear compensation (NLC) steps per span for optimum parameter values and the sensitivity of the BER to nonoptimum parameter values. The sensitivity to nonoptimum values is investigated as well for different transmission lengths and launch powers. It is shown that the optimum parameter values depend on the NLC step size, but that for a given step size representative values can be used for a range of transmission lengths and channel launch powers.