TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Component: The optical fiber comprises a glass optical fiber.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The optical fiber comprises quartz optical fiber. The radiation transmissive electrode of the first or second region is indium tin oxide, gallium indium tin oxide or zinc indium tin oxide. The acceptor material comprises a nanoparticle phase. The nanoparticle phase of the acceptor material the photosensitive organic layer of the first region or the second region consists of fullerenes and/or carbon nanotubes. The substrate of the frequency conversion region comprises upconversion material(s) comprising a Lanthanide series element.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The electrode surrounding the photosensitive organic layer of the first region or the second region comprises a metal comprising aluminum, gold, silver or copper or their alloys.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The upconversion material comprises 4-(dimethylamino)cinnamonitrile(cis or trans), trans-4-(4-(dimethylamino)styryl)-1-methylpyridinium iodide, 4-(4-(dimethylamino)styryl)pyridine, 4-(diethylamino)benzaldehyde diphenylhydrazone, trans-4-(4-(dimethylamino)styryl)-1-methylpyridinium p-toluenesulfonate, 2- (ethyl(4-(2-(4-nitrophenyl)ethenyl)phenyl)amino)ethanol, 4-dimethylamino-4'-nitrostilbene, Disperse Orange 25, Disperse Orange 3 and/or Disperse Red 1.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The optical fiber comprises a plastic optical fiber. The donor material comprises a polymeric phase comprising a conjugated polymer. The polymeric phase of the donor material of the photosensitive organic layer of the first region or the second region consists of poly(3-hexylthiophene) and/or poly(3-octylthiophene). The fullerenes comprise 1-(3-methoxycarbonyl)propyl-1-phenyl(6,6)C61. The first or the second region of the optical fiber further comprises exciton blocking layer(s) comprising a polymeric composite comprising nanotubes and/or fullerenes dispersed in poly(3,4-ethylenedioxythiophene) or poly(vinylidene fluoride).