Abstract: An active optical coupler between an optical bus line and subscribers. The optical coupler couples an emitting optical conductor and a receiving optical conductor and includes a diversion device that allows passage of a fraction of the incident light transmitted to the receiving conductor while diverting another fraction of this incident light energy to a photoreceiver which controls the injection of light energy into the optical coupler with a control in the form of a photoemitter for controlling the light energy transmitted to the receiving conductor with restoration of the level. A switch controls the operation of the photoemitter which in turn can be controlled either by the photoreceiver or by an input signal emitted by the subscriber. Digital data can be transmitted to subscribers by means of an optical bus line.