| 摘要 |
PURPOSE:To shorten an response time, by inputting beam into or outputting it from a light waveguide with a grating coupler while diffraction beam or non-diffraction beam is received at a group end of an optical fiber array to detect with a non-storage type photodetector at a branch end thereof. CONSTITUTION:A diverging beam 9 emitted from a semiconductor laser 3 is inputted from a tilted end face of a piezoelectric substrate 1 and reaches a grating coupler 18 loaded on the surface of a light waveguide 2 to be turned to a parallel beam 10. This parallel beam 10 is excited with a transducer 6 and after partially diffracted by a surface acoustic wave 13 absorbed with a damper 7, it is converted with a grating coupler 19 to two radiation beams, namely, non-diffraction and diffraction beams 11 and 12 condensing at one point. Then, the non-diffraction beam 11 and the diffraction beam 12 are taken out into air at the tilted end face 17 and condensed to points A and B separately on a group end 21 of optical fiber arrays 20. Then, beam condensed to the points A and B is inputted into an optical fiber composing the arrays 20 at the group end 21, sent to a branch end 22 and detected with the photodetector 23.
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