A power sourcing equipment (PSE) device of an optical power supply system includes a semiconductor laser that oscillates with electric power, thereby outputting feed light. The semiconductor laser includes a semiconductor region exhibiting a light-electricity conversion effect. A semiconductor material of the semiconductor region is a laser medium having a laser wavelength of 500 nm or less. A powered device of the optical power supply system includes a photoelectric conversion element that converts feed light into electric power. The photoelectric conversion element includes a semiconductor region exhibiting a light-electricity conversion effect. A semiconductor material of the semiconductor region is a laser medium having a laser wavelength of 500 nm or less.