Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus. What is Multimode Fiber Cable? Multimode fiber (MMF) is an optical fiber designed to carry multiple light propagation paths—or. Multimode Fiber (MMF) has a core diameter, typically 50–100 micrometers, has ability to transfer multiple modes of light through the fiber core, uses lower-cost electronics (LED, VCSEL) operates at the 850 nm and 1300 nm wavelength and is used for short distance interconnections (up to 550m). Single mode fiber optic cable is made up of a small diameter glass or plastic core surrounded by cladding, which is a layer of reflective material. Although they can do the same job in some instances, the different construction methods make each of them better suited to certain tasks and budgets. That makes picking between single mode and multimode fiber optic cables an. Unlike copper cables, which rely on electrical signals, fiber optics use pulses of light to transmit data—offering unmatched bandwidth, low interference, and long-distance capabilities. But not all fiber cables are created equal: multimode (MM) and single mode (SM) fibers are the two primary types.