250um bare fiber means the bare optical fiber with a soft plastic coating whose diameter is 250 microns. It consists of a central core which carries the light signal, using a cladding material whose diameter is 125 microns. We supply single-mode and multimode bare optical fiber cables which are manufactured by Corning for high speed, VCSEL laser-based local area networks (LAN) and local access networks. Our Corning bare fibers can help you to stay ahead of escalating network demands.