Performance of NRZ-versus RZ-WDM transmission around zero dispersion wavelength over dispersion-shifted fiber

Performances of nonreturn-to-zero (NRZ) and return-to-zero (RZ) wavelength-division-multiplexing (WDM) signals employing unequal channel spacing around zero-dispersion wavelength over dispersion-shifted fiber are compared by numerical simulation. In multirepeater WDM transmission systems employing installed dispersion shifted fiber, NRZ signals offer superior performance to RZ signals except in special cases.