| 摘要 |
PROBLEM TO BE SOLVED: To provide a light wavelength measuring device for having a stable temperature characteristic in a wide outer temperature range by using a function of a phase compensator having a refractive index temperature dependency. SOLUTION: This light wavelength measuring device includes a main beam splitter that splits a light beam to be measured into a first split light beam and a second split light beam and causes the first and second split light beams passing through different optical paths to be interfered with each other. The light wavelength measuring device further includes a wavelength plate that is disposed on at least one of the optical paths of the first and second split light beams, the phase compensator that is disposed on at least one of the optical paths of the optical paths of the first and second split light beams and has the refractive index temperature dependency, a polarized light beam splitter that splits interference light obtained by the above interfering in accordance with the polarization state, and a light sensing element that receives the interference light split by the polarized light beam splitter. The light wavelength measuring device includes a heating means attached to the phase compensator and a control circuit that controls temperature of the phase compensator by way of the heating means on the basis of the ambient temperature. COPYRIGHT: (C)2010,JPO&INPIT
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