NRZ vs. RZ in 10-40 Gbit/s dispersion-managed WDM transmission systems

Summary form only given. We compare NRZ and RZ modulation for wavelength-division multiplexing (WDM) systems operating up to 40 Gbit/s with as many as 16 channels. We find that in 10-40 Gbit/s dispersion-managed (single-mode fiber+dispersion-compensating fiber) systems, NRZ is more adversely affected than RZ by nonlinearity, which is the main degradation source. However, the difference between RZ and NRZ in a 16-channel 40-Gbit/s system is not very significant because dispersion becomes a key limiter. For /spl les/8 channels, RZ is almost always more optimal.