Patent ID: 7502403

Claim:
A semiconductor laser comprising: a semiconductor substrate; an active layer formed on a main surface of the semiconductor substrate which generates light; an optical waveguide for propagating the light that is generated from the active layer; a resonant cavity structure for optical feedback along the propagation direction; a mirror for reflecting the laser beam emitted from the cavity in a substrate rear surface direction; and a lens having a curved semiconductor surface at the substrate rear surface side for emitting the laser beam reflected by the mirror, wherein when the semiconductor substrate is in an xy plane of right-hand orthogonal coordinates, and the optical axial direction of the optical waveguide is in parallel to the x-axial direction, the normal direction to the mirror surface and the z-axial direction form an angle of 45°, and the laser beam is emitted in the substrate rear surface direction that is the negative direction of the z-axis, wherein the outer peripheral configuration of the lens, as viewed from the substrate rear surface side, is an oval configuration that satisfies the following relationship: a −2 x 2 +b −2 y 2 =1 where a and b are a radius in the x-axial direction and a radius in the y-axial direction, respectively, and satisfies a relationship of a<b; wherein a that represents the radius in the x-axial direction and b that represents the radius in the y-axial direction meets a relationship of 3 μm <a <b <200 μm.