Abstract: In a semiconductor element is shown having a silicon layer, a waveguide comprising silicon and a diode structure connected with external, conductive contacts. The diode structure is provided in such an arrangement to the waveguide that the diode structure can be influenced by electron hole pairs generated by photons in the waveguide. In order to create a semiconductor element with an optical waveguide and an integrated diode structure, in which high losses in the optical waveguide are avoided, the waveguide is weakly doped, and a germanium-rich layer is a component of the diode structure. The semiconductor element is well suited as a component in integrated optics for optical-electrical conversion.