Experimental Investigation of Dispersion Maps for 40 x 10 Gb/s Transmission over 1600 km of Fiber With 100-km Spans Employing Distributed Raman Amplification

We experimentally investigate the effect of dispersion maps on system performance in a 40x10-Gb/s WDM transmission over 1600 km fiber with 100-km spans employing distributed Raman amplification. We show that the system performance is critically dependent on the level of in-line dispersion compensation. Over (110%) and under (90%) per-span dispersion compensation yield similar high performance, however full (100%) per-span dispersion compensation leads to a severe penalty due to cross-phase modulation caused by re-alignment of bits between adjacent channels at each amplifier.