COMPARISON OF N X 40 GB S AND 4N X 10 GB/S WDM TRANSMISSION OVER STANDARD SINGLE-MODE FIBER AT 1.55 MU-M/

We compare the performance of dispersion-managed 4 x 40, 16 x 10, and 16 x 40 Gb/s wavelength-division-multiplexed transmission over 1000-km standard single-mode fiber operating at 1.55 mu m. It is shown, that for N x 40 Gb/s, the system performance is mainly limited by the degra dations of each single channel, No significant additional degradation due to cross-phase modulation or four-wave mixing could be observed. M oreover, it is shown that focusing on the total fiber-input power, bot h transmission schemes, 4 x 40 Gb/s at 100-GHz channel spacing and 16 x 10 Gb/s at 25-GHz channel spacing, yielding the same total bandwidth show almost identical performance.