This letter describes the four-wave-mixing (FWM) suppression effect of
dispersion varying fiber (DVF) whose chromatic dispersion increases (
or decreases) along its length. The FWM suppression performance is inv
estigated for the dispersion variation rate and its cycle number in th
e DVF. Moreover, it is clarified experimentally that the DVF functions
efficiently in wavelength division multiplexing (WDM) systems with an
input power of more than 10 dBm/ch.