Patent ID: 8363226

Claim:
An optical interference measuring apparatus comprising: a first multiple-wavelength light source configured to emit a light beam having a plurality of spectra; a second multiple-wavelength light source configured to emit a light beam having a wavelength different from that of the light beam emitted from the first multiple-wavelength light source and having a polarization component orthogonal to that of the light beam emitted from the first multiple-wavelength light source; a polarization optical element configured to separate the light beam emitted from the first multiple-wavelength light source and the light beam emitted from the second multiple-wavelength light source; a reference surface provided at a reference position and configured to reflect the light beam emitted from the second multiple-wavelength light source; a test surface provided at a test object and configured to reflect the light beam emitted from the first multiple-wavelength light source; a spectral optical element configured to divide interference signals of the light beams of the first multiple-wavelength light source and the second multiple-wavelength light source; a plurality of detectors configured to detect interference signals having single wavelengths of the light beams emitted from the first multiple-wavelength light source and the second multiple-wavelength light source with respect to a plurality of wavelengths based on the interference signals divided by the spectral optical element; and an analyzer configured to process signals obtained from the detectors to calculate an optical path difference between the reference surface and the test surface.