Multi-mode OM2, OM3 or OM4 fibre optic (50/125)

Multi-mode OM2, OM3 or OM4 fibre optic cable has 50/125µm cores and is generally used for backbone applications due to high capacity and reliability. Loose tube versions are ideal for external use and commonly available with SWA or CST mechanical protection. Tight buffered versions are designed for runs around multiple bends and not usually armoured. 

Multimode fibres have larger core diameters than single-mode so the light is reflected in a zigzag pattern down the core, resulting in higher attenuation rates (losses) than single-mode. 

The difference between multi-mode OM2, OM3, OM4 and OM1 cables is the optical fibre performance, please see our Fibre Optic Cable Selection Guide for more information.


Construction – Multi-mode OM2, OM3 or OM4 fibre optic
50/125µm fibres with coloured coating
fibres are either contained in a loose tube (LT) or tight buffered (TB)
optional steel wire armour (SWA) or corrugated steel tape armour (CST)
generally with low smoke zero halogen (LSZH) sheathing


Technical – Multi-mode OM2, OM3 or OM4 fibre optic
fibre diameter: core 50µm (micrometres), cladding 125µm
number of fibres: 4, 6, 8, 12, 16 or 24 core versions commonly available
loose tube (LT): fibres are enclosed within protective tube(s), usually with a water resistant gel
tight buffered (TB): fibres have an additional tough waterproof layer over the normal coating


A printable PDF specification is available here: Multi-mode OM2, OM3 or OM4 fibre cable (50/125).


For alternative fibre types return to the Fibre Optic Cables front page,
where our “Fibre Selection Guide” is also available.

Note: low smoke zero halogen / halogen free (LSZH, LSOH, LSHF, OHLS) should not be confused with LSF (low smoke and fume), an in-depth explanation is shown on our LSZH Control Flex front page.


All measurements should be considered nominal and images for illustration purposes only. Although Central Cables Ltd has made every reasonable effort to ensure its accuracy, the information contained herein is subject to error or omission and to change without notice. In no event will Central Cables Ltd be liable for any damages whatsoever, arising in connection with the information described.