Optoelectronic directional coupler for a bias-free control signal

Claim 1

Optoelectronic directional coupler including a) two mutually spaced, coupled led lightwave conductors extending in a coupling area, the conductors each being connected to a waveguide output on the directional coupler and two electrodes in the coupling area, with the aid of which the optical coupling between the coupled conductors can be acted on with the aid of a control signal, b) extra lightwave conductors, of which at least one is in communication with a wave conductor input on the directional coupler, the extra lightwave conductors being arranged such that an incoming lightwave on the directional coupler wave conductor input is divided between the extra lightwave conductors into two partial lightwaves, each having substantially the same power and being in phase with the other, or being phase-shifted half a revolution in relation to the other, characterized in that the coupled lightwave conductors (6a, 6b; 22a, 22b; 33a, 33b; 43a43b) are each connected to one of the extra lightwave conductors (8a, 8b; 36a, 36b; 46a, 46b) and in that the incoming lightwave (P) can be switched between the outputs (7a, 7b; 35a; 35b, 45a, 45b) of the directional coupler (1;30;40) by the partial lightwaves (P1,P2;P4,P5;P6,P7) being switched between the coupled lightwave conductors with the aid of the control signal (S) connected to one of the electrodes (5a; 34a; 44a), the signal assuming a positive (+VO) or a negative (-VO) potential on switching, in relation to a reference potential to which the other electrode (5b; 34b; 44b) is connected, the positive potential (+VO) having substantially the same numerical value as the negative potential (-VO).