System for transferring data with at least one channel between a rotating element and a fixed element by wireless optical communication, comprising, for each channel: - a rotating set of at least one rotating optical transmitter or receiver , mounted on and secured to the rotating element, - a fixed set of at least one fixed optical receiver or transmitter , mounted on and secured to the fixed element, - processing means in communication with said at least one transmitter of the rotating set or of the fixed set where applicable, wherein one of the rotating set and the fixed set comprises a plurality of optical transmitters or receivers distributed annularly around the rotating element, the other one of the rotating set and the fixed set comprises at least one optical receiver or transmitter disposed substantially at the same height with respect to the rotation axis of the rotating element, as the plurality of optical transmitters or receivers distributed in a ring, the fixed and rotating sets are arranged so that, whatever the angular position of the rotating element, where applicable said at least one optical receiver of the other one of the rotating set and the fixed set receives optical signals transmitted by at least one transmitter in said plurality of optical transmitters distributed annularly, or at least one receiver of said plurality of optical receivers distributed annularly receives optical signals transmitted by at least one optical transmitter of the other one of the rotating set and the fixed set, the processing means are arranged to generate, independently of the angular position of the rotating element, an electrical signal and to transmit, to said at least one transmitter in the rotating set or the fixed set as applicable, said electrical signal so that, if there is more than one transmitter in this set, these transmitters simultaneously transmit the same optical signal, characterized in that one of the rotating set and the fixed set comprises a plurality of optical transmitters installed in series. - a rotating set of at least one rotating optical transmitter or receiver , mounted on and secured to the rotating element, - a fixed set of at least one fixed optical receiver or transmitter , mounted on and secured to the fixed element, - processing means in communication with said at least one transmitter of the rotating set or of the fixed set where applicable, one of the rotating set and the fixed set comprises a plurality of optical transmitters or receivers distributed annularly around the rotating element, the other one of the rotating set and the fixed set comprises at least one optical receiver or transmitter disposed substantially at the same height with respect to the rotation axis of the rotating element, as the plurality of optical transmitters or receivers distributed in a ring, the fixed and rotating sets are arranged so that, whatever the angular position of the rotating element, where applicable said at least one optical receiver of the other one of the rotating set and the fixed set receives optical signals transmitted by at least one transmitter in said plurality of optical transmitters distributed annularly, or at least one receiver of said plurality of optical receivers distributed annularly receives optical signals transmitted by at least one optical transmitter of the other one of the rotating set and the fixed set, the processing means are arranged to generate, independently of the angular position of the rotating element, an electrical signal and to transmit, to said at least one transmitter in the rotating set or the fixed set as applicable, said electrical signal so that, if there is more than one transmitter in this set, these transmitters simultaneously transmit the same optical signal, characterized in that one of the rotating set and the fixed set comprises a plurality of optical transmitters installed in series. <EOS>