Apparatus and method for measuring chromatic dispersion

A chromatic dispersion measuring apparatus comprising:

• a pump light source for emitting pump light with a wavelength λpump;
• a probe light source for emitting probe light with a wavelength λprobe;
• a measuring means for measuring the power of idler light having a wavelength λidler output from a device under test according to four-wave mixing generated by propagation of the pump light and the probe light through the device;
• and
• an analysis tool for calculating the chromatic dispersion of the device at a specific wavelength λpump on the basis of the results obtained by seeking the generation efficiency of idler light relative to the wavelength λprobe when the pump light having a specific wavelength is propagated and by detecting the frequency difference or wavelength difference between the pump light and the probe light that makes an extremum of generation efficiency of the idler light and by calculating the phase mismatch among the pump light wavelength having such frequency difference or wavelength difference, the corresponding probe light wavelength, and the corresponding idler light wavelength in the device.