Also MMF

A type of optical fiber normally 50/125 or 62.5/125 using many modes of light.

Multi-mode fibers are described using a system of classification determined by the ISO 11801 standard — OM1, OM2, and OM3 — which is based on the modal bandwidth of the multi-mode fiber. OM4 (defined in TIA-492-AAAD) was finalized in August 2009, and was published by the end of 2009 by the TIA. OM4 cable will support 125m links at 40 and 100 Gbit/s. The letters “OM” stand for optical multi-mode.

OM1: Basic type of MultMode Typically used for serial transmission using LED in the 850nm or 1300nm windows. This is no longer a recommended fiber in infrastructure standards.

OM2: Type of MultMode Fiber Not comonly used as it has limited advantages over other fiber types.

OM3: Type of Lazer Optimzed Multmode Fiber Earliest optimized version of multimode fiber to support VSEL lazer interfaces to offer higher speeds and distances.

OM4: Type of Lazer Optimzed Multmode Fiber Optimized version to support multiple gigabit Ethernet using VCSELs ,such as 10GBASE-SR

OM5: Type of Lazer Optimzed Multmode Fiber also supportive of Wide Band Signaling. ISO have defined OM5 to support WB signaling on MMF, referred to as WBMMF as and it will be optimized to support wavelengths in the 850 nm to 950 nm range. This latest specification fiber ensures not only more efficient support for future applications to useful distances, but also complete compatibility with legacy applications