A GaAs‐based photovoltaic converter for optical-to-electrical power conversion and for data transmission was developed. the device structure is based on a modified GaAs solar cell structure having a lattice‐matched Ga0.51In0.49P window layer. the converter consists of an array of series-connected photovoltaic cells. the input optical laser power is transmitted via a single optical multimode fibre and distributed homogeneously to the separate cells. One of the cells has separate connections for acting as a light-emitting diode for data transmission in the opposite direction. the conversion eficiency of the individual cells was measured to be 49%, and the array conversion efficiency was 41%.