Single-mode fibers are best for long-distance outside runs. OM5 fiber is used in a wide range of cable assemblies, including trunk cables and fiber optic backbones. That includes small cell cables and fiber optic. The topic of this article, OM5 fiber, is a multimode fiber cable designed for high-bandwidth, short- to medium-range applications. It's the first approved wideband multimode fiber (WBMMF) for applications that use two fibers to transmit at 40-100 Gbps using shortwave wavelength-division. OM (Optical Multimode) fiber comes in five generations. Core Size Evolution OM1 has a. Most multimode fiber types used today are OM3/OM4 and OM5, but there are still older network infrastructures, where cables inside buildings were laid a long time ago that use OM1, OM2 multimode fiber.