Unrepeatered Transmission Over 670.64 Km Of 50g Bpsk, 653.35 Km Of 100g Ps-Qpsk, 601.93 Km Of 200g 8qam, And 502.13 Km Of 400g 64qam

We report the results of 50G, 100G, 200G, 400G un- repeatered transmission aimed at achieving the longest distance without any inline active elements, this system realizes record single-carrier 50 Gb/s (PM-BPSK), 100 Gb/s (PS-QPSK), 200 Gb/s (PM-8QAM) and 400 Gb/s (PM-64QAM) unrepeatered transmission over 670.64 km with 103.95 dB span loss, 653.35 km with 101.27 dB span loss, 601.93 km with 93.3 dB span loss, and 502.13 km with 77.83 dB span loss, respectively. This is achieved using optimized high-order Raman pumps, cascaded RGUs and coherent modulation format with concatenated FEC. G.654.E fiber with ultra-low loss & 130 mu m(2) effective area is used as span fiber.