Transmission of 40x200-Gb/s Polarization Division Multiplexed Quadrature Phase Shift Keyed channels over Ultra-Long-Haul Distances

We demonstrate ultra-long-haul transmission of 40 channels at 200-Gb/s over more than 6,000 km. This result is obtained using PDM-QPSK modulation format, coherent detection, ultra low-loss large effective area fiber and erbium-doped fiber amplifiers. OCIS codes: (060.2360) Fiber optics links and subsystems; (060.4080) Modulation; (060.4510) Optical communications.]