| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for achieving multiple channel forming of a photo-coupler 3 while suppressing an increase in size of the photo-coupler 3.SOLUTION: A photo-coupler comprises: an electric optical crystal substrate 331 having a periodical polarization inversion structure; and a light source section 31 for emitting a light beam passing through the electric optical crystal substrate 331. On the electric optical crystal substrate 331, a plurality of first electrodes 333 are arranged. Each of the first electrodes 333 forms a diffraction grating at a diffraction efficiency ratio &eegr; corresponding to an applied application electric signal Sip in a corresponding grating formation range R1 inside the electric optical crystal substrate 331. Therefore, the plurality of the grating formation ranges R1 individually modulate the light beam L1 incident on the electric optical crystal substrate 331, corresponding to the respective diffraction efficiency ratios &eegr; so as to constitute channels different from each other. In this way, the plurality of the grating formation ranges R1 (channels) individually modulate the light emitted from the same light source section 31, corresponding to the respective diffraction efficiency ratios &eegr;. |
