A semiconductor optical device includes an active layer, the active layer including a plurality of quantum well layers having gain peak wavelengths different from one another in a layering direction thereof, and a plurality of barrier layers, wherein the quantum well layers and the barrier layers are alternately layered over each other, and an n-type dopant has been added in the plurality of quantum well layers having gain peak wavelengths different from one another and in the plurality of barrier layers.

In an embodiment, an edge-emitting semiconductor laser diode includes a growth substrate, a semiconductor layer sequence located on the growth substrate, the semiconductor layer sequence having an active layer and an etch stop layer and two facets located opposite each other, wherein the facets bound the semiconductor layer sequence in a lateral direction, wherein the semiconductor layer sequence includes two edge regions adjoining the facets and a central region directly adjoining both edge regions, wherein, within each of the edge regions, a volume fraction of the active layer in the semiconductor layer sequence is smaller than in the central region, wherein the active layer is spaced apart from one facet, wherein a distance of the active layer to the facet varies along a direction parallel to this facet, and wherein the etch stop layer is arranged between the growth substrate and the active layer.