3. Data units in Networks

3.5. Fibre optic cable

Completely different from the transmission medium discussed earlier is fibre optic cable, due to the different materials used for the core. In the case of coaxial and twisted pair cable, the core or wire is copper, while in the case of fibre optic cables we are dealing with glass fibre. The use of glass fibre as the core building material also requires different types of transmission signals. In the case of copper media, this is electric current, in the case of optical fibre, light, the most commonly used type being infrared light.

1. Construction:

·         core - has a higher refractive index,

·         coating - has a lower refractive index,

·         paint protection coating,

·         reinforcement coating to protect the core during installation,

·         outer shell.

We can also find the following types of connectors:


·         LC

·         MT - RJ

·         MU

·         DIN


 

2. Types of fibre optics:

As with copper and optical fibre, we can discuss the different types of this medium. The most common divisions are single-mode and multimode optical fibres.

In the case of single-mode optical fibres, only one beam of light passes through the glass core, resulting in the so-called signal blurring phenomenon, i.e. signal attenuation.

Using this type of optical fibre, signals can be transmitted over long distances without signal amplification equipment.

In multimode fibre, a larger portion of the beam is sent through the core, resulting in a higher degree of signal blur compared to single-mode fibre. This is because each beam sent through the core must travel a different path from the sender to the receiver.

That is why multimode optical fibre is used over short distances, up to a few kilometres.

Another difference between single-mode and multimode optical fibre is the core diameter used. For single-mode fibre optics, this is between 8 and 10 micrometres [μm], while for multimode fibre optics it is 50 or 62.5 micrometres.