For the 1600 km transmission performance, we observe a smooth transition from the linear to nonlinear regime for all three fiber types and for both baud rates, as the launch power is increased; see Fig. 3(a) and (b). The data points represent measured results and the lines are computed using the NLI model [3] together with our calibrated Tx/Rx performance. The solid (dashed) lines represent completely incoherent (partially coherent) addition of nonlinear noise span to span. The details of this computation are described in Section. IV. The observed ∼1.5–2dB launch power advantage in the linear regime for SMF and LAF (for both 32 and 28 Gbaud) corresponds to the lower per-span loss of SMF and LAF compared to MDF. From Table I, we expect 18.9 dB of loss for 90 km of MDF and 17.1 dB of loss for 90 km of SMF. However, in our experiments, we achieve ∼20 dB and ∼18 dB, respectively; due to monitoring taps at both the input and output of the inline amplifiers(all NLI model computations use these effective per-span loss measurements). While the dB/km loss coefficient of LAF is lower than in SMF, our splice losses between the LAF to SSMF jumper cables yield per-span losses nearly identical to SMF. Thus, in the linear regime SMF and LAF exhibit similar performance and a lower loss LAF span would shift the linear response to lower launch powers [to the left in Fig 3(a) and (b)]. However, the measured BER minima that marks the transition into the nonlinear regime occurs at a higher per-channel launch power in LAF as expected from the lower nonlinear coefficient.