摘要 |
Linear polarized light beams are separated by wavelength separation filters 28a, 28b, and 28c, and make incidence with every two wavelength components either into a polarized light conversion element 20b or into polarized light conversion element 20c, and the optical paths for the light beams separated into two by the polarized light conversion element 20a are joined to form one light beam path for every waveform component. The optical signals of the four wavelength components are reflected either by a mirror 31b or by a mirror 31c, are converged by such as a hologram lens 40c, and, after being reflected by a mirror 32, are detected for every wavelength component by the photo detector array 36.
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