Optical semiconductor device

Abstract

An optical semiconductor device both capable of recording and reproducing information with respect to plural optical disks having different track pitches and capable of shortening an assembly time and achieving a cost reduction without the need to make a highly-precise assembly adjustment is provided. An optical semiconductor device is constituted by a semiconductor laser element, an emitted light beam branching element for branching a light beam emitted from the semiconductor laser element into a main beam and a plurality of sub beams, an objective lens for focusing the main beam and the sub beams onto an optical disk, and a light-receiving element for signal detection for detecting each of the main beam and the sub beams reflected by the optical disk. Further, a light distribution of the sub beams branched by the emitted light beam branching element has a shape equal to or narrower in an optical disk radial direction than a shape obtained by bisecting a light distribution of the main beam when the sub beams enter the objective lens.

Dependencies are inferred from the claim text.