Adopted by TIA, the nomenclature for multimode fiber found in the ISO/IEC 11801 standard includes the prefix “OM.” Rather than the spiritual mantra you hear in yoga class, most sources in our industry state that the acronym OM comes from “optical multimode” which seems rather obvious. But when it comes to the various nuances of each type of OM, the differences aren’t quite as obvious. There are currently five types of OM fiber—OM1, OM2, OM3, OM4 and OM5. OM1 fiber was the de facto choice for fiber throughout the 1980s and 1990s, and was still installed into the early 2000s. OM1 has a core diameter of 62.5 µm while OM2, OM3, OM4 and OM5 all feature a 50 µm core.
Sourced through Scoop.it from: www.flukenetworks.com