| 摘要 |
To provide an apparatus for measuring chromatic dispersion when modulating frequency of a variable wavelength light source is different from modulating frequency of a fixed wavelength light source for reference.This apparatus is provided with a variable wavelength light phase comparator 24 for obtaining a phase difference phix-phix' between a variable wavelength light component and a signal having the first modulating frequency fmx, a fixed wavelength light phase comparator 25 for obtaining a phase difference between a phase difference phi0-phi0' between a fixed wavelength light component and an electrical signal having the second modulating frequency fm0, a phase difference converter 26 for converting the phase difference phi0-phi0' calculated by the fixed wavelength light phase comparator 25 into phiex, which corresponds to the first modulating frequency fmx, and a true phase difference calculator 27 for measuring a true phase difference phi between the phase difference phix-phix' calculated by the variable wavelength light phase comparator 24, and the converted result phiex of phase difference converter 26, and obtains the true phase difference phi from which an affect of contraction/extension of a DUT 30 is removed when the first modulating frequency fmx and the second modulating frequency fm0 are different, thereby measuring wave dispersion.
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