Patent ID: 6925101

Claim:
A semiconductor laser device comprising a laminate structure consisting of a semiconductor layer of first conductivity type, an active layer and a semiconductor layer of second conductivity type, which is different from the first conductivity type, that are stacked in order, said laminate structure having a waveguide region to guide a light in a direction perpendicular to the direction of width, said waveguide region being formed by restricting the light from spreading in the direction of width in the active layer and in the proximity thereof, wherein the waveguide region has a first waveguide region and a second waveguide region, the first waveguide region being a region where light is confined within the limited active layer by means of a difference in the refractive index between the active layer and the regions on both sides of the active layer by limiting the width of the active layer, and the second waveguide region being a region where the light is confined therein by providing effective difference in refractive index in the active layer.