| 摘要 |
PURPOSE:To miniaturize a system and to attain a high speed access by forming a polarization diffraction grating and an optical detecting element on a same substrate, and executing a detection of a focus error signal and a tracking error signal by a different optical detecting element in an orthogonal direction. CONSTITUTION:A polarization diffraction grating 28 and optical detecting elements 30a-30f are formed on a same substrate having a waveguide layer 27, and plural areas 28a-28c to differentiate a grating direction in an orthogonal condition are formed in the polarization diffraction grating 28. A part of the optical detecting elements 30a-30f are made into the optical detecting elements 30a-30c for a focus error signal detecting to light-receive a waveguide light Pa to be diffraction-waveguided by another area 28a of the polarization diffraction grating 28, and a part of the optical detecting elements are made into the optical detecting elements 30e and 30f for a tracking error signal detecting to light-receive waveguide light beams Pb and Pc to e diffracton- waveguided by the other areas 28b and 28c of the polarization diffraction grating. Thus, an optical pickup structure can be miniaturized and lightened in weight, and an access time can be shortened. |
