| 摘要 |
PURPOSE:To obtain an optical coupler which permits reduction of size and does not require the adjustement of coupling by mounting molume type holograms through a low refractive index layer on an optical waveguide. CONSTITUTION:Transmission volume type holograms 13 are mounted via a low refractive index layer 12 on an optical waveguide 11 formed on a substrate 10. The refractive index of the layer 12 is set lower than those of the waveguide 11 and the holograms 13. The light from a coherent output light source 16 is made incident to the inside of the hologram materials 13 through a lens system 15, and is deffracted by gratings 14, then the light of the specific wavelength is coupled to the optical waveguide 11. It is equally well to constitute reflection volume type holograms by providing a metallic reflection layer on said transmission volume type holograms so that the incident light is reflected and diffracted by the gratings and the metallic reflection layer. |
