Patent ID: 7852890

Claim:
A semiconductor laser comprising: a semiconductor substrate; a semiconductor stacking body including a waveguide core formed on said semiconductor substrate, a cladding layer formed above said waveguide core, and a contact layer; a diffraction grating with a period determining an oscillation wavelength and formed in a manner that does not impart a change in oscillation direction to an output wavelength; and an electrode; wherein said diffraction grating is formed along said waveguide core so as to appear in the surface of said cladding layer, said contact layer is formed along said waveguide core on a region other than a region where said diffraction grating appears in the surface of said cladding layer, each of a period direction of said diffraction grating and a longitudinal direction of said contact layer is in parallel in a longitudinal direction of said waveguide core, said electrode is provided on said contact layer, and said diffraction grating is formed right above a current injection region of said waveguide core, the current injection region being a region where current injection is performed through said electrode to amplify light.