This paper investigated the impact of receiver dispersion slope compensation for 40-Gb/s transoceanic transmission over conventional nonzero dispersion shifted fibers. Various differential phase-shift keying (DPSK) modulation formats were experimentally compared at 42.8 Gb/s [to account for forwarded error correction (FEC) overhead] with dispersion slope compensators at the receiver. These transmission measurements were performed in a circulating loop over a transatlantic distance of 6250 km using a variety of channel spacings, relative polarizations, and synchronous modulation techniques. All formats benefited from receiver dispersion slope compensation. For orthogonally polarized channels on 133-GHz spacing, the return-to-zero DPSK (RZ-DPSK) format performed the best; all channels (18 × 40 Gb/s) propagated with > 13.5-dB Q-factor and with > 4-dB FEC margin. Whereas for copolarized channels on 100-GHz spacing, carrier-suppressed return-to-zero (CSRZ)-DPSK performed the best; all channels (25 × 40 Gb/s) propagated with > 3-dB FEC margin. Moreover, it was shown that parallel launch only suffered a penalty of \sim 0.2 and \sim 0.5 dB relative to the orthogonal launch for 133-and 100-GHz channel spacing, respectively. Finally, it was demonstrated that copolarized 40 Gb/s RZ-DPSK worked as well as 10 Gb/s RZ-ON-OFF keying (RZ-OOK) for the same spectral efficiency (30%) over the 6250 km of conventional nonzero dispersion shifted fibers (NZ-DSF) originally designed for 10 Gb/s transmission.
© 2006 IEEE
Jin-Xing Cai, Carl R. Davidson, Morten Nissov, Haifeng Li, William T. Anderson, Yi Cai, Li Liu, Alexei N. Pilipetskii, Dmitri G. Foursa, William W. Patterson, Patrick C. Corbett, Alan J. Lucero, and Neal S. Bergano, "Transmission of 40-Gb/s WDM Signals Over Transoceanic Distance Using Conventional NZ-DSF With Receiver Dispersion Slope Compensation," J. Lightwave Technol. 24, 191- (2006)