Device for bidirectional wireless communication by visible or invisible light, comprising at least (a) one or more transmitter modules, each transmitter module comprising: - a light source which is powered by a control means and emits an amplitude and/or phase modulated light; - a control means which generates an electrical signal derived from the digital/analogue conversion of source data to be transmitted; (b) a receiver module comprising: - a photodetector illuminated by said modulated light and generating a modulated electrical signal (14, 15) in response to said modulated light; - a processing module for the signal generated by said photodetector which is designed to communicate with the control means via the return path; - an electronic means which is located between the photodetector and the signal processing module and able to adjust the impedance of the photodetector in order to maximise the throughput rate of transmitted data while minimising the distortion of the signal received; characterized in that the photodetector is a photovoltaic module and said electronic means for adjusting impedance is configured to vary the impedance of the photodetector in successive increments as a function of a control signal corresponding to an acceptable quality criterion (CQ_Acc), and to maximise the level of the electric signal received, provided that a criterion representing the quality of the electrical signal received is better than said acceptable quality criterion (CQ_Acc). (a) one or more transmitter modules, each transmitter module comprising: - a light source which is powered by a control means and emits an amplitude and/or phase modulated light; - a control means which generates an electrical signal derived from the digital/analogue conversion of source data to be transmitted; - a light source which is powered by a control means and emits an amplitude and/or phase modulated light; - a control means which generates an electrical signal derived from the digital/analogue conversion of source data to be transmitted; (b) a receiver module comprising: - a photodetector illuminated by said modulated light and generating a modulated electrical signal (14, 15) in response to said modulated light; - a processing module for the signal generated by said photodetector which is designed to communicate with the control means via the return path; - an electronic means which is located between the photodetector and the signal processing module and able to adjust the impedance of the photodetector in order to maximise the throughput rate of transmitted data while minimising the distortion of the signal received; - a photodetector illuminated by said modulated light and generating a modulated electrical signal (14, 15) in response to said modulated light; - a processing module for the signal generated by said photodetector which is designed to communicate with the control means via the return path; - an electronic means which is located between the photodetector and the signal processing module and able to adjust the impedance of the photodetector in order to maximise the throughput rate of transmitted data while minimising the distortion of the signal received;