Nonlinear-Penalty Free Single-Carrier >600 Gbit/s Entropy-Loaded DP-PCS-256QAM Transmission Over 2 km NANF with Launch Power of 39 dBm

We experimentally demonstrate a single-carrier digital subcarrier multiplexed (DSM) transmission over 2 km nested anti-resonant nodeless fiber (NANF) with a net bit-rate of 613 Gbit/s, enabled by the entropy-loaded dual-polarization probabilistic constellation shaping 256 quadrature amplitude modulation (DP-PCS-256QAM). Even under 39 dBm launch optical power, nonlinear-penalty free transmission is achieved.