Transmission of Mixed 224-Gb/s and 112-Gb/s PDM-QPSK at 50-GHz Channel Spacing Over 1200-km Dispersion-Managed LEAF® Spans and Three ROADMs

By using asymmetric interleavers, carrier-suppressed polarization-division-multiplexed quadrature-phase-shift-keying (CSRZ-PDM-QPSK), and coherent detection, we successfully transmit a mix of 224-Gb/s and 112-Gb/s PDM-QPSK channels at a 50-GHz channel spacing and 3-b/s/Hz spectral efficiency over 1200-km dispersion-managed LEAF® spans with three ROADMs and over 2000 km without ROADMs.