Fibre optic cables are constructed in two ways: loose Tube and tight buffered. Both contain a type of strengthening member, such as aramid yarn, stainless steel wire strands, or gel-filled sleeves. Each, however, is designed for very different environments.
Loose tube cables are designed for harsh environment conditions in the outdoors. They protect the Fibre core, cladding, and Coating by enclosing everything within fairly rigid protective sleeves or tubes. Many loose tube cables contain a water resistant Gel surrounding the fibres. The gel helps protect the fibres from moisture, making the cables ideal for high humidity environments, where water or condensation may otherwise be problematic. Tight buffered cables may be easier to install, because there is no gel to clean up and it does not require a fan out kit for Splicing or termination.
A system of classification determined by the ISO 11801 standard determines that fibre optic cables can then be:
- OM1 – 62.5/125 and 50/125 Multi-Mode Fibre
- OM2 – 62.5/125 and 50/125 Multi-Mode Fibre
- OM3 – 50/125 Multi-Mode Fibre
- OS1 – Single Mode
- OS2 – Single Mode