US Patent 9618672 Uniform illumination light diffusing fiber device

An illumination device comprising: (i) a light diffusing optical fiber having a numerical aperture of NALDF, wherein said light diffusing optical fiber has an outer surface, two ends, and a core, the fiber comprising a region with a plurality of scattering structures within said core configured to scatter guided light via said scattering structures towards the outer surface providing scattering-induced attenuation greater than 50 dB/km at illumination wavelength, wherein said scatter guided light diffuses through said outer surface to provide illumination; (ii) a light source having a numerical aperture of NAS1, said light source being optically coupled to one end of said light diffusing optical fiber; NALDF−NAS1>0.05.