Fiber optic cable is available with a variety of performance capabilities for a variety of applications. This makes interoperability between these options an issue to consider before installation. As an aid to help installers match up compatible products the industry has standardized on specific colors to indicate a fiber optic component’s performance characteristics. The two components where this is applies are cable and connectivity (connectors, coupler ports, adapters, etc.).
Multi-mode (OM1/2, OM3/4, OM4+) fiber has a core size of 50 microns or 62.5 microns and is used for shorter cable lengths. The large cores allow multiple beams to travel down the core. It is typically used as a backbone for general data and voice applications between floors and close buildings on campus.
Single-mode(OS1/2) is used for long cable lengths. The smaller core uses a single beam that follows the core, thus being faster and brighter and provides higher bandwidth. Typically used for extreme long distances, high speed, telco backbones, CATV networks, etc.
Mixing of OM3, OM4 and/or OM4+ will result in performance that meets only the lowest performing type used. For consistent performance all components should be the same.
Some fiber optic cables will include different types within the same jacket making the jacket color neutral regarding performance. Refer to print legend on jacket to identify fiber classifications.
Do not interconnect PC, UPC and/or APC connectors. Doing so will result in high return loss and damaged connectors.
Blue jacketed cable is sometimes used to designate a specialty polarization-maintaining fiber optic cable.
Black jacketed cable is sometimes seen in UV resistant, outdoor rated cable.
Why do I see single-mode OS2 described with a 9 micron core size?
OS2 (and the obsolete OS1) has a core size of 8.3 microns, but many sources will simply round up that number to 9 microns in their descriptions. It is the same cable whether described as 8.3 or 9 micron.