A light diffusing optical fiber includes a glass core, a cladding, a phosphor layer surrounding the cladding, and a plurality of scattering structures positioned within the glass core, the cladding, or both. The phosphor layer includes two or more phosphors and is configured to convert guided light diffusing through the phosphor layer into emission light such that the color of the emission light has a chromaticity within a u′-v′ chromaticity region on a CIE 1976 chromaticity space defined by: a first u′-v′ boundary line and a second u′-v′ boundary line that extend parallel to a planckian locus at a distance of ±0.02 Duv from the planckian locus, a third u′-v′ boundary line that extends along an isothermal line for a correlated color temperature of about 2000 K, and a fourth u′-v′ boundary line that extends along an isothermal line for a correlated color temperature of about 10000 K.