| 摘要 |
A delay time measurement apparatus for an optical element includes a pulse light source, wavelength setting unit, optical power divider, optical delay unit, controller, and detector. The pulse light source can vary the wavelength of light to be output, and outputs an optical pulse having a predetermined repetition period. The wavelength setting unit sets the wavelength of light to be output from the pulse light source. The optical power divider divides the optical pulse output from the pulse light source into a first optical pulse and a second optical pulse to be input to an optical element as the object to be measured. The optical delay unit can vary the spatial optical path length along which the first optical pulse divided by the optical power divider travels. The controller changes the spatial optical path length of the optical delay unit. The detector receives a measurement optical pulse output from the optical element as the object to be measured, and a reference optical pulse output from the optical delay unit, and detects the delay time of light that has passed through the optical element as the object to be measured from a change in spatial optical path length required for superposing the measurement and reference optical pulses on each other.
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