Optical Fibre Invention: 6 Key Facts & History

The optical fibre invention was not a single eureka moment. It took over a century of work by physicists, engineers, and material scientists across four continents. The key breakthrough came in 1966 when Charles K. Kao predicted that purified glass could carry light signals over long distances — a prediction that earned him the 2009 Nobel Prize and made the modern internet possible.

Here is what we cover: 6 key milestones in the invention of optical fibre, from Colladon's 1840s water-jet demonstration to the erbium-doped amplifier that let fibre span oceans.

1. Colladon's Light Fountain (1842)

Swiss physicist Jean-Daniel Colladon wanted his lecture audience to see what happened inside a falling jet of water. He piped sunlight into the stream. The light got trapped inside the curving water, bouncing off the inside surface and following the arc down — a glowing, bending thread of light. He described it in Comptes Rendus in 1842.

Britain's John Tyndall demonstrated the same effect in famous lectures from 1854 and is often wrongly given sole credit. The principle at work is total internal reflection — the same physics that runs the internet today.

Think of it like a water slide. The light enters the stream at a shallow angle and cannot escape: the water-air boundary acts like a wall, bouncing the light back in. Colladon's audience saw a glowing arc of water and had no idea they were watching the birth of fibre optics.

2. Bell's Photophone (1880)

Alexander Graham Bell invented the photophone in 1880, just four years after the telephone. It transmitted voice on a beam of sunlight reflected off a vibrating mirror. The receiver converted the fluctuating light back into sound.

The photophone worked over distances of several hundred metres. Bell called it "the greatest invention I have ever made, greater than the telephone." But it had a fatal flaw: clouds, fog, and rain blocked the beam. Free-space light transmission was unreliable.

The photophone was not fibre optics — there was no glass fibre guiding the light. But it proved that light could carry voice, and it planted the idea that communications could be optical.

3. Kapany Coins "Fiber Optics" (1950s)

The term "fiber optics" was coined by Indian-American physicist Narinder Singh Kapany. He introduced it in a 1960 article in Scientific American that brought the concept to a wide audience.

But Kapany's real contribution came earlier. In 1953, working with Harold Hopkins at Imperial College London, he built bundles of glass fibres that could transmit images. Each fibre carried one tiny pixel of the picture. The bundles were flexible and could be bent around corners.

This work led directly to the first practical flexible gastroscope, patented in 1956 by Basil Hirschowitz, C. Wilbur Peters, and Lawrence Curtiss at the University of Michigan. For the first time, doctors could see inside a patient's stomach without rigid tubes. Medical endoscopy was born, and fibre optics had its first commercial application.

4. Kao's Prediction (1966)

Charles K. Kao of Standard Telecommunication Laboratories in England made the decisive breakthrough in 1966. He asked a simple question: why did existing glass fibres lose so much light?

The accepted answer was that light scattering was a fundamental property of glass. Kao proved this was wrong. He showed that the loss came from impurities — iron, copper, and water molecules trapped in the glass. Purify the glass, he argued, and fibre could carry signals over 100 km.

Kao predicted a target of 20 dB/km — at the time, the best fibres lost over 1000 dB/km. He calculated that one fibre pair could carry 200,000 telephone channels. Many were sceptical. Kao shared his 2009 Nobel Prize in Physics for this work.

Here is the key idea: Kao's insight was that the problem was chemistry, not physics. The limit was not in the laws of nature. It was in the manufacturing process. Clean the glass, and everything changes.

5. Corning Makes It Real (1970)

In 1970, a team at Corning Glass Works in New York — Robert Maurer, Donald Keck, and Peter Schultz — produced the first fibre that beat Kao's target. They reached 17 dB/km by doping silica glass with titanium.

The breakthrough was the manufacturing process. They used a vapour deposition technique to create ultra-pure glass, building up layer after layer of silica soot. The resulting fibre was about 100 times clearer than anything before it.

By 1981, Corning had reduced attenuation to 0.2 dB/km at 1550 nm — 100 times better than Kao's original target. Modern submarine fibre achieves as low as 0.14 dB/km.

6. The Amplifier That Spanned Oceans (1987+)

Low-loss fibre could carry signals tens of kilometres, but crossing an ocean required hundreds. The solution was the erbium-doped fibre amplifier (EDFA), developed independently by David N. Payne at the University of Southampton and Emmanuel Desurvire at Bell Labs in 1986–87.

The EDFA is a short section of fibre doped with erbium ions. A pump laser excites the erbium, which then amplifies the signal passing through — all inside the fibre itself, without converting to electricity. This eliminated the need for expensive electronic repeaters every 50 km.

The EDFA made wavelength-division multiplexing practical. By sending many colours of light down the same fibre, each colour carrying its own data channel, the capacity exploded. A single fibre pair today can carry hundreds of terabits per second.

The first transatlantic fibre cable, TAT-8, began service in 1988. By 2026, over 600 submarine cables span the world's oceans, carrying about 99% of intercontinental data traffic.

Timeline of the Optical Fibre Invention

A Common Misconception: John Tyndall Invented Fibre Optics

Many sources credit John Tyndall with discovering the principle of fibre optics through his 1854 public lecture demonstrating light in a water jet. Tyndall's demonstration was influential — but it was not original.

Colladon performed the same experiment 12 years earlier and published it in 1842. Tyndall himself credited Colladon in his writing. The misconception persists because Tyndall was a more famous lecturer who wrote popular science books that spread the idea widely.

The lesson: fibre optics history is a chain of contributions, not a single inventor. Colladon showed light could be guided. Kapany showed it could carry images. Kao showed it could carry data. None of them did it alone.

External resources

• Charles K. Kao — Nobel Prize Facts — official Nobel Prize page with biography, interview, and prize motivation
• Wikipedia: Optical Fiber — History — detailed history section covering Colladon, Tyndall, Kapany, Kao, and Corning with references
• The Story of Optical Fiber (Corning) — manufacturer's account of the 1970 breakthrough and the development of modern fibre

For the physics that makes fibre optics work, see our guide on total internal reflection. For an introduction to how fibre carries signals, start with what is optical fiber. And for the different types of fibre that came from these inventions, read types of fiber optic cable.

Recommended Products

• Complete Fibre Optic Starter Kit on Amazon — includes cables, connectors, and tools for learning fibre optics
• Fibre Optic Inspection Microscope on Amazon — handheld 200×–400× microscope for examining connector end-faces
• Book: City of Light — The Story of Fiber Optics — Jeff Hecht's definitive history of fibre optics and optical communication