How Fiber Optics works?

Now that you know what an optical fibre means, we should focus on the specific details of how the technology works.

Basically, data travels through a fibre optic cable as a pulse of light propagated along the cable via reflection. At this point, you are probably thinking: Fine, but HOW does it work?

To answer this question, let’s give a real life example.

For instance, imagine you and your friend are taking a walk and you come to a long –very long- and winding tunnel. You walk through the tunnel while your friend who happens to be afraid of the dark stays back. Now imagine that you want to see your friend by shining your flashlight through the tunnel. The problem is that you can only see as far as the first bend in the tunnel since light travels in a straight line and the tunnel is curved. What would the solution be? Well, you would need to set up a series of angled mirrors at each bend so that the light can bounce on the reflective surfaces and finally reach your friend. Well this is essentially how optical fibre works!

In this example, the light shining from the flashlight is similar to the data transmitted as light through optical fibre cables. The light signals are transmitted from one end, and each tiny photon (particle of light) bounced successively off a series of mirrors through the cable to reach the opposite end. The glass itself acts as a mirror. In order for optical fibres to transmit data over long distances, the fibres must therefore be highly reflective.


Now that you are aware of everything you need to know about optical fibre as a telecommunications medium, let’s look at how it is used in the fibre to the home broadband technology. More precisely, let’s see what “to the home” means in this specific communication infrastructure. First, back to you, the user of Internet services via devices in your home premises. As you know, you must subscribe to Internet broadband via a telecoms operator. This allows you to upload and download data via a broadband connection. The network (remember the tunnel example) may use optical fibre in some parts of the network, but not in others.

An access network architecture in which the final connection to the subscriber’s premises is optical fibre. The fibre optic communications path terminates on or inside the premises for the purpose of carrying communication services to a single subscriber.

In order to be classified as FTTH, the fibre access must reach the boundary of the subscriber’s premises and terminate:
 inside the premises, or
 on an external wall of the subscriber’s premises, or
 no more than 2m from an external wall of the subscriber’s premises.