Patent ID: 7006207

Claim:
A polarization mode dispersion measuring device for measuring polarization mode dispersion of a device under test, said polarization mode dispersion measuring device comprising: polarization separating means for receiving light having emitted from the device under test, separating said received light into p-polarized light and s-polarized light, and outputting the p-polarized light and s-polarized light; light generating means for generating first incident light and second incident light both having a common wavelength; first optical modulation means for applying a first intensity modulation with a first intensity modulation frequency to said first incident light, and emitting first modulated light; second optical modulation means for applying a second intensity modulation with a second intensity modulation frequency different from said first intensity modulation frequency to said second incident light, and emitting second modulated light; polarization combining means for combining said first incident light and said second incident light having been applied with the first and second intensity modulations, and emitting combined incident light; light input means for making said combined incident light incident to the device under test, wherein said first incident light is in line with a p-polarization axis in said polarization separating means, and said second incident light is in line with an s-polarization axis in said polarization separating means; first measuring means for measuring phase shift equivalent values of a component of said first incident light in the output of said polarization separating means; second measuring means for measuring phase shift equivalent values of a component of said second incident light in the output of said polarization separating means; and polarization mode dispersion measuring means for measuring a polarization mode dispersion of the device under test based on measurement results of said first measuring means and said second measuring means.