An optical wireless power transfer system includes a transmission module, which includes a main light source configured to output a main light; a transmitting processor configured to modulate the main light to have a first modulation; a beam splitter configured to pass the main light as a power light; and a reception module. The reception module includes a retro-reflector configured to retro-reflect the main light back to the transmission module; and a receiving processor configured to control the retro-reflector to reflect the main light to have a second modulation based on a power generated by the main light. Further, the beam splitter is further configured to reflect the main light having the second modulation to a first photodiode included in the transmission module.