Unrepeatered Transmission of 400Gb/s over 557km and 100Gb/s over 590km with Single Fibre Configuration

We demonstrate unrepeatered transmission of 400Gb/s $(4\times 128Gb/s)$ over 557km and 100Gb/s over 590km distance with single fibre configuration using forward and backward ROPAs enabled by 2 nd -order Raman pumping and large $A_{eff}$ ultra-low-loss fibre.