9 Tb/s Transmission Using 29 mW Optical Pump Power Per EDFA With 1.24 Tb/s/W Optical Power Efficiency Over 15,050 km

We transmit 143x32.6 GBd 8D-QPSK signal over 15,050 km with EDFAs consuming 29 mW of 980 nm-pump power. We experimentally achieve record optical power efficiency from 6.5 to 1.24 Tb/s/W with the corresponding optimum spectral efficiency from 2.4 to 2.0 b/s/Hz for transmission distances ranging from 6,020 to 15,050 km respectively. These results are enabled by: precisely tuned information spectral efficiency and EDFA output power based on our power efficiency model to maximize optical power efficiency; the use of coded modulation format with <1.6 dB gap to Shannon limit and variable overhead FEC; the use of ultra-low loss fiber; more power efficient gain equalization with a single gain flattening filter per two EDFAs; and low back-to-back implementation penalty. We also confirmed the validity of our power efficiency model comparing the designed and measured OSNR evolution, achieved optical power efficiency and the corresponding spectral efficiency.