For each loop configuration (different fiber type) and for each baud rate, we varied the per-channel launch power from−6dBm to +6 dBm. At each launch power, we performed an OSNR versus BER scan by loading ASE noise at the receiver. For the 28 GBaud tests, we extracted the required OSNR to achieve the hard-FEC BER of 10−3 and for the 32 GBaud experiments, we extracted the required OSNR for the soft-FEC BER limit of 10−2 .