  We propose a very simple method for measuring the zero-dispersion wavelength
of an optical fiber as well as the ratio between the third- and fourth-order
dispersion terms. The method is based on the four wave mixing process when
pumping the fiber in the normal dispersion region, and only requires the
measurement of two spectra, provided that a source tunable near the
zero-dispersion wavelength is available. We provide an experimental
demonstration of the method in a photonic crystal fiber and we show that the
measured zero-dispersion wavelength is in good agreement with a low-coherence
interferometry measurement.
