A power over fiber system comprising: a first data communication device including a power sourcing equipment including a semiconductor laser configured to oscillate with electric power, thereby outputting feed light; a second data communication device including a powered device including a photoelectric conversion element configured to convert the feed light output by the power sourcing equipment into electric power, the second data communication device being configured to perform optical communication with the first data communication device; and an optical fiber cable having one end connectable to the first data communication device and another end connectable to the second data communication device to transmit the feed light and signal light (125, 325), wherein the electric power obtained by the conversion by the photoelectric conversion element is driving power for the second data communication device, wherein the optical fiber cable includes: a core that is configured to transmit the signal light (125, 325); a first cladding, being a graded-index multimode light transmission path, that is positioned in contact with periphery of the core and configured to transmit the feed light; and a second cladding that is positioned in contact with periphery of the first cladding, wherein radial refractive index distribution of the first cladding is distribution in which refractive index gradually decreases from a local maximum at an internal point toward points where the first cladding is in contact with the core and the second cladding, respectively, the internal point being away from the core and the second cladding, and wherein the refractive index of the core is higher than the refractive index of the first cladding at the point where the first cladding is in contact with the core. a first data communication device including a power sourcing equipment including a semiconductor laser configured to oscillate with electric power, thereby outputting feed light; a second data communication device including a powered device including a photoelectric conversion element configured to convert the feed light output by the power sourcing equipment into electric power, the second data communication device being configured to perform optical communication with the first data communication device; and an optical fiber cable having one end connectable to the first data communication device and another end connectable to the second data communication device to transmit the feed light and signal light (125, 325), wherein the electric power obtained by the conversion by the photoelectric conversion element is driving power for the second data communication device, wherein the optical fiber cable includes: a core that is configured to transmit the signal light (125, 325); a first cladding, being a graded-index multimode light transmission path, that is positioned in contact with periphery of the core and configured to transmit the feed light; and a second cladding that is positioned in contact with periphery of the first cladding, wherein radial refractive index distribution of the first cladding is distribution in which refractive index gradually decreases from a local maximum at an internal point toward points where the first cladding is in contact with the core and the second cladding, respectively, the internal point being away from the core and the second cladding, and wherein the refractive index of the core is higher than the refractive index of the first cladding at the point where the first cladding is in contact with the core.