An optical sensor in which photo currents generated by light in the visible and infrared wavelength ranges are to be tapped separately at pn junctions of active regions. The active regions include n- or p-doping and are formed in a p-substrate 52. The optical sensor comprises a surface-near first active region 12, and a second active region 14 subjacent to the first active region 12 and forming together with the first active region 12 a pn junction 22 that is short-circuited. A third active region 20 is subjacent to the second active region 14 and forming together with the second active region a further pn junction 23. Together with a fourth active region 24 subjacent to the second active region 20, a further pn junction 25, 29 is formed together with the third active region 20 and the substrate 52.