As their name suggests, these cables contain several fibres in jackets (900 µm, 2 mm or 3 mm), single-mode or multi-mode. The cables and transitions can be configured to your requirements. All connectors are inspected and tested at 850 nm (MM) and 1550 nm (SM), test data supplied. The Series +. 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. Multi-mode fiber has a fairly large core diameter that enables multiple light modes to be. To recap Optical Fiber can be divided into Multimode Fiber (MMF) and Single-Mode optical fiber (SMF).