Multimode vs. Singlemode Fibre

Multimode fibre cable has a large-diameter core and therefore has multiple modes of propagation—that is, several wavelengths of light are used in the fibre core. It’s primarily used for lighter- capacity or shorter-distance applications.

Multimode fibre
Core Diameter:
50, 62.5, or 100 microns
Cladding diameter: 125 microns

In contrast, single-mode fibre cable has a small core and only one mode of propagation. With only a single wavelength of light passing through its core, single-mode prevents wavelengths of light from overlapping and distorting data, which can happen with multimode fibre.

What does this get you?
Distance—up to 50 times more distance with single-mode versus multimode. Consequently, single-mode is typically used in 10-/100-Mbps network connections spread out over extended areas, including cable television and campus backbone applications.

Phone companies have now turned to single-mode fibre cables because they get longer distances with fewer repeaters and a larger bandwidth - resulting in a lower cost.

Single-mode fibre
Core Diameter :7.1 or 8.5 microns
Cladding Diameter :125 microns

You also get higher bandwidth. You can use a pair of single-mode fibre strands full-duplex for up to twice the throughput of multimode fibre cable.

The actual distance you achieve with single-mode fibre will vary according to the manufacturer of the LAN devices used with the cable. This is because although there’s an established standard for multimode fibre cable, there is, as of yet, none established for single-mode fibre optic cable.