OPTICAL FIBER POWER FEEDING SYSTEM

In order to improve optical power feeding efficiency, this optical fiber power feeding system is provided with: a power feeding device 110 including a semiconductor laser 111 that performs laser oscillation by electric power and outputs power feeding light 112; a power receiving device 310 including a photoelectric conversion element 311 that converts the power feeding light into electric power; an extension unit 360 that extends the wavelength of the power feeding light; a first optical fiber cable 280A for transmitting the power feeding light from the power feeding device to the extension unit; and a second optical fiber cable 290A for transmitting the power feeding light from the extension unit to the power receiving device. On the basis of the loss - transmission distance characteristic of a laser wavelength λ1 before the extension by the extension unit and the loss - transmission distance characteristic of a laser wavelength λ3 after the extension by the extension unit, the first optical fiber cable is configured to have a length less than or equal to a transmission distance L2 at which a loss of the laser wavelength before the extension becomes equal to a loss of the laser wavelength after the extension.