Fibre Optics – How Does It Do It?

Growing up in the 90s it was hard for anyone not to have heard of fibre optics.  We all loved those lamps designed like a UFO. You know the ones, the lamp that had the dome of lights on top!

Oh go on then;

fibreoptic Fibre Optics   How Does It Do It?


This was actually a revival from the 70s but I’m not that old!

I wanted to start with this as it quite nicely shows how fibre optics work extremely well.

So to start; there’s a light at the base, on top of the light is a multi-coloured disc which spins, on top of this is hundreds of plastic strands barely thicker than a hair. The light travels through the cable to the tips.


Well it’s about to get a bit more technical. Now we have the basics under our belts.

So we understand that light goes in one end then travels down a plastic tube (fibre optic cable) and comes out the other end.

Jump forward forty years to today and think about the fibre optic broadband with superfast speeds. The principle is effectively the same. Data enters one end travels down the tube then comes out the other end. We all know that light travels extremely fast so it makes sense to integrate this.

In order to send information through Fibre optics you need four fundamental items;

A Transmitter – This produces and encodes the light signals

Lots of Optical Cables – To transport the light signal

An Optical Regenerator – This essentially is a pit stop to boost the signal

An Optical receiver – To receive and decode the light signals

Instead of using a transmitter and an optical receiver at both ends, optical transceivers are available. An Optical Trasceiver is capable of both sending and receiving light signals.

How this works?

Take a long strand of flexible hair thin glass, surround that by two layers of plastic. This will create total internal reflection meaning the light will bounce all the way along the glass from end to end.

Data is sent by a laser switching on and off billions of times a second to create a lightning fast morse code which is then decrypted by the transceiver.

You can carry a signal down some optical cable without the need of a regenerator for upto 100miles!!

So next time you walk down your street imagine the billions and billions of tiny lights flashing back and forth beneath your feet! That would be amazing to see wouldn’t it?