Basics of networking

Introduction

Fibre optics carry information in the form of light pulses. Thanks to the phenomenon of total internal reflection, light running inside an optical fibre is trapped there. It is therefore possible to transmit information over a much greater distance without loss than with copper cables.

Light that travels inside an optical fibre is attenuated. As no method has been invented to produce a perfectly reflective optical fibre, the phenomenon of optical power loss occurs. At present, optical fibre cables are capable of transmitting information over a maximum distance of around 100 km without loss. Thanks to the use of optical amplifiers at certain intervals, we can connect very distant locations via optical fibre networks.

The quality of fibre-optic networks is primarily influenced by the quality of the work carried out during its laying. Attention should be paid to:

• the maximum bending radius of the cable - depending on the standard the bending radius is: 30, 10 7.5 mm,
• the quality of the cutting equipment - after cutting, the edge of the optical fibre must not be frayed,
• quality of the welding machine 

Examples of defects

One way to test a fibre optic cable is to use a visual fault locator:

• Correct optical fibre 

• and damaged

The above damage most likely occurred by exceeding the bending radius of the optical fibre.