Optical detector, optical pickup and optical information reproducing apparatus using optical pickup

摘要

An optical pickup has a semiconductor laser having two laser sources of different wavelengths disposed in the same package, one diffraction grating and one optical detector. A plurality of light reception areas each having four divisional light reception planes of a <CUSTOM-CHARACTER FILE="US06567355-20030520-P00900.TIF" ALT="custom character" HE="20" WI="20" ID="CUSTOM-CHARACTER-00001"/>-character shape are disposed at positions where light beams reflected from an optical disc are applied. A focus error signal is generated by an astigmatism method by using independently these light reception areas and a tracking error signal is generated by a differential phase detection method by using one or both the light reception areas.