Light-coupling systems and methods that employ light-diffusing optical fiber are disclosed. The systems include a light source and a light-diffusing optical fiber optically coupled thereto. The light-diffusing optical fiber has a core, a cladding and a length. At least a portion of the core comprises randomly arranged voids configured to provide substantially spatially continuous light emission from the core and out of the cladding along at least a portion of the length. A portion of the light-diffusing optical is embedded in an index-matching layer disposed adjacent a lower surface of a transparent sheet. Light emitted by the light-diffusing optical fiber is trapped within the transparent sheet and index-matching layer by total internal reflection and is scattered out of the upper surface of the transparent sheet by at least one scattering feature thereon.