A QUICK NOTE ON SPELLING

Before we dive into the history, you might see this technology spelled in two different ways. In the UK and most of the world, it is spelled fibre optics. In the USA, it is spelled fiber optics. Since we are looking at this from a global perspective (and because the key theory was developed in Britain), we will mostly use the spelling "fibre" in this article.

EARLY ATTEMPTS: BENDING LIGHT IN WATER

Long before the internet existed, scientists were trying to figure out if light could travel in anything other than a straight line. The first person to prove it was possible was a Swiss physicist named Daniel Colladon in the early 1840s.

In a famous demonstration, he shone a light into a tank of water. When he opened a spout to let the water pour out in a curved stream, the light followed the curve of the water rather than shining straight out. This phenomenon is called "total internal reflection" and it is the basic physics principle that makes modern broadband possible. However, using water streams wasn't exactly practical for connecting computers!

THE FATHER OF FIBRE OPTICS: CHARLES K. KAO

By the mid-20th century, doctors were using short glass fibres to look inside the human body (endoscopes). But these fibres were useless for long-distance communication because the light would fade away after just a few metres. The glass simply wasn't clear enough.

Enter Charles K. Kao. In the 1960s, Kao was working at Standard Telecommunication Laboratories (STL) in Harlow, UK. While others were trying to improve copper wires, Kao had a radical idea. He theorised that the problem wasn't the physics of the glass, but the impurities inside it.

In 1966, he published a groundbreaking paper proposing that if we could make glass that was chemically pure, we could transmit light signals over kilometres without losing the data. He is widely recognised today as the "Father of Fibre Optics" and was awarded the Nobel Prize in Physics in 2009 for this discovery.

MAKING THE IMPOSSIBLE GLASS

Kao had the theory, but he didn't have the glass. The challenge was now manufacturing. The race was on to create the purest glass ever known to man.

The breakthrough happened in the USA at Corning Glass Works. In 1970, a team of researchers including Robert Maurer, Donald Keck, and Peter Schultz invented a wire made of silica glass with titanium. It was capable of carrying 65,000 times more information than copper wire.

This was the turning point. Within a few years, telephone companies began replacing their old copper infrastructure with these new glass cables. It started a revolution that would eventually allow us to move from simple voice calls to the high-speed internet we use today.

THE NEED FOR SPEED: COPPER VS FIBRE

Why did we go through all this trouble to invent glass cables? The difference in performance is staggering. Click on a technology below to see how fibre changed the game compared to the old copper networks.

GOING UNDERWATER AND GLOBAL

Once Corning perfected the glass, the next step was connecting the world. In 1988, the first transatlantic fibre optic cable, TAT-8, was laid between the USA, the UK, and France. Before this, international calls were expensive and mostly carried by satellite, which had a noticeable delay.

TAT-8 could carry 40,000 simultaneous telephone calls. Today's modern subsea cables can carry millions of terabits of data per second. There are now hundreds of these cables sitting on the ocean floor, acting as the physical internet that connects continents. Without Charles K. Kao's initial theory, none of this global connectivity would exist.

TIMELINE OF KEY EVENTS