45.7 Tb/s Over 12 053 km Transmission in an All-Multi-Core-Amplified Recirculating Loop

We present a recirculating-loop-based long-haul transmission system that achieves the longest reach ever reported in multi-core fiber transmissions relying on a fully integrated multi-core amplification scheme without the use of fan-in/fan-out devices. Our system successfully transmits 45.7 Tb/s using $\mathbf {4\times 175\times 24.5}$ GBd PDM 4-QAM signals over 12053 km of weakly-coupled 4-core fiber, enabled by multi-core C-band EDFAs and distributed Raman amplification. Additionally, we evaluate the performance of 16-QAM and 64-QAM signals within the same recirculating loop, estimating total decoded throughputs of 90.8 Tb/s after 3161.6 km and 137 Tb/s after 395.2 km, respectively.