n this work we have presented the WDM systems signal parameters dependency on the number of WDM channels, modulation types and intervals between WDM systems signals. The results show the dispersion impact on total number of channels, modulation, interval and bit rate. To enlarge one of them or change the modulation scheme, the total dispersion impact will increase. To reduce the impact of SRS using one of the technical solution practically not feasible, but to decrease the input power level will decrease the SRS too. When the channel interval in WDM systems is increased the effect of XPM decreases. SPM will decrease, if the total level of dispersion will be reduced. In WDM systems where the total dispersion level is compensated the SPM will not appear.