5 is a u03bb 4 wafer or a quarter wave plate having an ordinary refractive index n o and an extraordinary refractive index n ao u03bbvac pr u03bb here indicates the light wavelength in a vacuum an electric field is applied to polarizer 5 by means of a control unit 51 permitting adjustment of the polarization direction of the light on the basis of the pockels effect or the kerr effect the current furnished by control unit 51 can be regulated in dependence on the current flowing through the photodiode 1 the latter has electrical terminals 11 via from which control unit 51 receives a control current the manufacture of such a circuit arrangement corresponds in every way to known manufacturing processes in succession further semiconductor layers of different compositions are epitaxially deposited on the semiconductor substrate 10 and are doped as required in order to change the electrical conductivity or the refractive index optical waveguide 4 is also produced epitaxially it is composed of semiconductor layers or silicon compounds e g silicon dioxide silicon nitride in a lithography step the waveguide 4 is provided with a recess into which the polymer plastic forming polarizer 5 is introduced after the remaining components have been covered then the electrical contacts for photodiode 1 semiconductor laser 2 and polarizer 5 are vapor deposited through a contact mask.