How do Fibre Optic Cables Transmit Data?

Nowadays, almost all internet providers deliver internet to your house through fibre optic cables instead of satellite or copper connections. Fibre optic cable transmits data using light instead of an electrical current. It has several advantages over the old internet transmission technology, so more and more consumers are opting for services such as the National Broadband Network (NBN).

While most people are aware that an optical fibre delivers a faster, more reliable internet service, they may not know how fibre optic technology works. Therefore, we will explain how fibre optic cable transmits data. But first, let’s explore what optical fibre is.

A fibre optic or optical fibre is a thin strand of glass through which information gets transmitted as light pulses. Fibre optics as a transmission medium is capable of carrying signals at very high speeds over long distances, making it superior to traditional copper networks.
A fibre optic cable can contain a number of glass fibres. The glass strand carrying the data has an outer glass layer with a different refractive index, which keeps the light travelling through the core of the fibre. This allows signals to travel long distances with very minimal attenuation (loss).

An optical fibre is a transmission medium that has three main parts, including the outer jacket/coating, cladding, and core.

The core is the most crucial part of an optical fibre cable and is made up of special glass with a very low refractive index.

Another glass layer surrounds the core, known as the cladding. The cladding reflects light and allows the light beam to travel down the core and reach the receiver with minimal loss. So, an optical fibre relies on the total internal reflection phenomenon to transmit data.

Finally, the core and the cladding are wrapped in an outer jacket/coating to protect it from damage. The outer coating also helps to absorb shock and gives extra protection to the optical fibre.

Now let's move into the final section of this article, where we will reveal how an optical fibre cable transmits data.

Data is transmitted as light instead of power as used in copper cable. However, just like traditional power-based networks, the data is in the form of bits and bytes of information or essentially binary code. It does this faster and more reliably than copper cables due to the speed at which light travels. Additionally, fibre optic cables are designed to minimise attenuation and eliminate interference from outside power sources. The added benefit is security, as light is not as susceptible as power to malicious interference e.g. hacking.

There are many advantages to running fibre optic networks versus traditional copper networks. You should now have a basic understanding of what a fibre optic cable is, how it is constructed, and how data is transmitted via light using fibre optic technology. Fibre networks deliver a fast, secure and reliable internet service.