6-mode SDM transmission over 960 km with a reach extension of 5 times enabled by a 6M-EDFA

For the first time, we present 6-mode transmission over 960 km, 5 times longer than before, enabled by an in-line 6-mode Er-doped fiber amplifier. A Gaussian-like Er-doping profile has been proposed to reduce the differential modal gain to 1.15 dB.