Abstract: A light source comprises a light-emitting device (1) emitting electromagnetic radiation from an emitting surface (18) and an optical element (2) having a light input surface (21), a light output surface (22) and side surfaces (23) connecting the light input surface (21) to the light output surface (22). The light input surface (21) is located in the optical path of the light-emitting device (1), the electromagnetic radiation entering the optical element (2) through the light input surface (21), and the light input surface (21) has a concave curvature and an area being smaller than the area of the light output surface (22).

Abstract: An optoelectronic semiconductor chip is specified, which has an active zone (20) containing a multi quantum well structure provided for generating electromagnetic radiation, which comprises a plurality of successive quantum well layers (210, 220, 230). The multi quantum well structure comprises at least one first quantum well layer (210), which is n-conductively doped and which is arranged between two n-conductively doped barrier layers (250) adjoining the first quantum well layer. It comprises a second quantum well layer (220), which is undoped and is arranged between two barrier layers (250, 260) adjoining the second quantum well layer, of which one is n-conductively doped and the other is undoped. In addition, the multi quantum well structure comprises at least one third quantum well layer (230), which is undoped and which is arranged between two undoped barrier layers (260) adjoining the third quantum well layer.