Fibre optic data cables

The development of fibre optics is a direct result of the growing demand for fast data transmission between different terminals. Given its immunity to electromagnetic interference and its characteristics in terms of signal transmission, fibre optics are the ideal support for high-speed data transmission.

DEFINITION

The optical fibre is a very thin glass cable transmitting light signals on which digital data is carried.
The transmission factor for fibre optics, expressed in decibels (dB), gives its data-transmission quality.

TYPES OF FIBRE OPTIC

Single-mode fibre optic
	The core is very thin and enables light to flow in what is practically a straight line. This type of fibre is frequently used for telecom services, connections over very long distances (several miles) and in backbones (a term used to refer to the "nerve centre" of a high-speed network).
	Categories OS1 Diameter 9/125 µm Throughput ≥ 10 Gbits/s Bandwith ≥ 25 Gbits.km
Multi-mode, step-index fibre optic
	The core is thicker than the cladding. This type of fibre is very effective over short distances, but is not often used.
Multi-mode, graded-index fibre optic
	The core is thicker than the cladding. This type of fibre is very effective over short distances, but is not often used.
	Categories OM1 OM2 OM3 Diameter 62.5/125 µm 62.5/125 µm, 50/125 µm 50/125 µm Throughput 100 Mbits/s to 1Gbits/s ≤ 1 Gbit/s ≤ 10 Gbit/s Bandwith for 850 mm 200 Mhz.km 500 MHz.km 1500 MHz.km Bandwith for 1350 nm 500 Mhz.km 500 MHz.km 500 MHz.km

COMPONENTS OF A FIBRE OPTIC CABLE

Optical waves spread along the optical core made of silica, melted quarz or plastic. The core diameter ranges from 50µm to 200µm.
The optical cladding ensures the optical waves remain in the core. The light ray spreads as it is repeatedly reflected against the barriers formed by the optical cladding. The protective covering, usually a plastic layer with a thickness of between 25 and 1000 microns, gives the fibre excellent mechanical properties.

ADVANTAGES

- Most reliable and secure transmission method
- Very high data transmission speed, up to 100Gb/s
- Low signal reduction: support transmission over long distances (multi-mode fibre)
- Immunity against electromagnetic interference
- No electromagnetic radiation
- Discrete, 100% secure link
- Corrosion resistance