Light diffusing optical fiber bundles, illumination systems including light diffusing optical fiber bundles, and methods of affixing light diffusing optical fiber bundles to polymer optical fibers are disclosed. A light diffusing optical fiber bundle includes an optically transmissive jacket and a plurality of light diffusing optical fibers disposed within the optically transmissive jacket. Each of the plurality of light diffusing optical fibers includes a glass core including a plurality of nano-sized voids. The plurality of light diffusing optical fibers extend along a length of the optically transmissive jacket such that the plurality of diffusing optical fibers are not interwoven.