32 x 40-Gb/s dense WDM transmission over 3000 km using "double-hybrid" fiber configuration

This paper reports long-distance transmission experiments of 100-GHz-spaced 32 /spl times/ 40 Gb/s dense wavelength-division-multiplexing (DWDM) signals, designed for submarine applications. A transmission distance of 3000 km was obtained with more than 11.9-dB Q value. Keys to the achievement are the use of a novel "double-hybrid" fiber configuration and a nonlinear tolerant carrier-suppressed return-to-zero signal format for effectively suppressing the self-phase-modulation group-velocity-induced waveform degradation. The advantage of this double-hybrid fiber configuration is also confirmed by a transmission performance comparison with a "quadruple-hybrid" fiber configuration using 40-Gb/s-based DWDM signals.