Transmission of mixed 260-Gb/s PDM-16QAM and 130-Gb/s PDM-QPSK over 960-km and 4160-km dispersion-managed SSMF spans

We transmit a mix of 260-Gb/s polarization-division-multiplexed 16-ary quadrature-amplitude modulation (PDM-16QAM) and 130-Gb/s polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) channels at a 50-GHz channel spacing in a dispersion-managed (DM) system with standard single-mode-fiber (SSMF) spans. We study the impact of pulse shaping, time interleaving of polarizations and maximum likelihood (ML) detection techniques on the performance of the system. We show that the pulse shaping and ML detection can increase the transmission distances of the PDM-16QAM channels and PDM-QPSK channels by 50% and 10%, respectively. With 20% overhead hard-decision forward-error-correction (FEC) coding, we successfully transmit the 260-Gb/s PDM-16QAM and 130-Gb/s PDM-QPSK channels over 960-km and 4,160-km, respectively, in the DM system.