Dispersion measurement device and dispersion measurement method

A dispersion measurement device measuring a wavelength dispersion amount of a measurement object having positive or negative group delay dispersion, the dispersion measurement device comprising:

• a light source configured to output a first optical pulse;
• a pulse converter including a spatial light modulator configured to present a phase pattern for generating modulated light by applying a predetermined phase shift for each wavelength to the first optical pulse, the pulse converter forming an optical pulse train from the first optical pulse, and the optical pulse train being the modulated light including a plurality of second optical pulses having a time difference from each other and having center wavelengths different from each other, the phase pattern including a pattern for giving a group delay dispersion having a sign opposite to the group delay dispersion of the measurement object to the first optical pulse;
• an optical detector configured to detect a temporal waveform of the optical pulse train;
• an arithmetic processor electrically connected to the optical detector;
• and
• a controller storing a first phase pattern that is the phase pattern for giving a positive group delay dispersion to the first optical pulse and a second phase pattern that is the phase pattern for giving a negative group delay dispersion to the first optical pulse, the controller configured to selectively output the first phase pattern and the second phase pattern to the spatial light modulator, wherein
• the controller is configured to:
• store the first phase pattern for imparting the positive group delay dispersion and the second phase pattern for imparting the negative group delay dispersion;
• receive information indicative of whether the group delay dispersion of the measurement object is negative or positive;
• and
• selectively output the first phase pattern when the group delay dispersion of the measurement object is negative, and selectively output the second phase pattern when the group delay dispersion of the measurement object is positive;
• the measurement object is arranged on an optical path between the light source and the pulse converter, or an optical path between the pulse converter and the optical detector, and
• the arithmetic processor is configured to estimate the wavelength dispersion amount of the measurement object based on a feature amount of the temporal waveform.