Optical pickup, optical recording and/or reproducing apparatus using the same, and method for detecting tracking error signal

摘要

An optical pickup and an optical recording and/or reproducing apparatus employing the optical pickup, wherein the optical pickup includes: a light source; an objective lens to collect and focus an incident beam on an information storage medium; a holographic grating to split light emitted by the light source into a main beam and first and second sub-beams by diffraction and to provide, or create, a continuously changing wavefront in the first and second sub-beams to reduce the amplitude of an AC component of a sub-push-pull (SPP) signal of the first and second sub-beams; and a photodetector to receive the main beam and the first and second sub-beams that are focused on and reflected from the information storage medium and to obtain a main push-pull (MPP) signal of the main beam and a SPP signal of the first and second sub-beams.