US Patent 7903709 Semiconductor laser device and method of manufacturing the same

A semiconductor laser device includes a substrate and a semiconductor layer formed on a surface of the substrate and having a waveguide extending in a first direction parallel to the surface, wherein the waveguide is formed on a region approaching a first side from a center of the semiconductor laser device in a second direction parallel to the surface and intersecting with the first direction, a first region separated from the waveguide on a side opposite to the first side of the waveguide and extending parallel to the first direction and a first recess portion separated from the waveguide on an extension of a facet of the waveguide, intersecting with the first region and extending in the second direction are formed on an upper surface of the semiconductor laser device, and a thickness of the semiconductor layer on the first region is smaller than a thickness of the semiconductor layer on a region other than the first region.