| 摘要 |
PURPOSE:To prevent a grating coupler from the generation of flaws or the adhesion of dirt causing light dispersion or the deterioration of condensing characteristics by covering the surface of the grating coupler or an optical waveguide including the coupler with a material having a refractive index lower than that of the optical waveguide. CONSTITUTION:A buffer layer 12 consisting of SiO2 is formed on a substrate 11 and the optical waveguide layer 13 consisting of a glass layer having a refractive index higher than that of SiO2 is formed on the surface of the layer 12. The grating coupler 14 is formed on the surface of the layer 13 and a protection layer 15 consisting of a material having a refractive index lower than the layer 13 is formed on the coupler 14. The end part 16 of the layer 13 is formed by cleavage or grinding, the wave-guided light 13 is energized by a semiconductor layer and light 18 is radiated to space by the coupler 14. Since the surface of the layer 13 including the coupler 14 is coated with the material having a refractive index lower than that of the layer 13 to form the layer 15, the coupler can be prevented from the generation of flaws or the adhesion of dirt causing light dispersion or the deterioration of condensing characteristics. |
