| 摘要 |
PURPOSE:To easily load many optical elements to a substrate with good accuracy and to attain a compact and light optical pickup by distributing and disposing the respective types of the optical elements to both the sides of the substrate constituting an optical waveguide path. CONSTITUTION:A grating coupler 20 as a polarizing diffraction grating is loaded on the surface of a waveguide path layer 17 so as to confront a semiconductor laser 11. Further, on the surface of the waveguide path layer 17, two grating beam splitters 21 provided with an equal interval straight line grating as a division diffraction grating are loaded so as to be adjacent to the grating coupler 20. Four photodetectors 22 are laminated and formed on the last end part of the waveguide path layer 17. On the surface opposite to the waveguide path layer 17 forming side surface of a waveguide path element 13, namely on the surface opposite to the grating coupler 20 loading surface, a 1/4 wavelength plate 14 is disposed and loaded and further, on the upper surface of the 1/4 wavelength plate 14, a Fresnel type objective lens 15 is laminated and loaded. |
