| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical unit capable of detecting a large number of light beams having different wavelengths, at low cost. SOLUTION: The optical unit includes a filter member 1 for separating a transmitted light beam and a photodetector 2 having a plurality of light-detecting elements. The filter member 1 includes a light-transmitting substrate; a plurality of protruding parts formed of metal member on one surface of the substrate; and a metal oxide film formed so as to cover the plurality of protruding parts and the surface of the substrate with an oxide metal material, having a refractive index higher than that of the metal material. The plurality of protruding parts are arranged so that the metal oxide film present between adjacent protruding parts forms a diffraction grating and the protruding part forms a waveguide. At least one of a grating period of the diffraction grating, the height of the protruding part, and the thickness of the metal oxide film is set at a different value for each part so that the wavelength of light beam transmitted through the filter member is changed for each part. In the photodetector 2, each of the plurality of light-detecting elements 21 is arranged so as to receive the light beam transmitted through the filter member 1. COPYRIGHT: (C)2011,JPO&INPIT
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