Hi,
I am trying to compare between NRZ and RZ modulation formats.
Practically, it has been demonstrated numerically and experimentally that the conventional
nonreturn-to-zero (NRZ) modulation format is superior compared to the return-to-zero (RZ) modulation
when dealing with large WDM systems, as RZ modulation causes a significant Eye Closure Penalty near end channels.
The results obtained in this tutorial will be used to compare the Eye Closure Penalties for both NRZ and RZ cases,
as well as the effects of nonlinearities.
The advantage of RZ format in terms of transmission
distances was recently demonstrated in a long-distance wavelength
division multiplexing (WDM) transmission experiment though most WDM transmission experiments conducted
so far have used NRZ formats [6]. WDM signals, which were
initially NRZ but modified before transmission, were successfully
transmitted over transoceanic distances in a recirculating
loop. Time-division multiplexing (TDM) transmission experiments
, of course, use RZ signal formats, which allow
optical MUX-DEMUX to be easily carried out. The relative
advantages of NRZ or RZ formats are, however, still unclear
even in single-channel long-distance transmission.
Thanks,