More than 40 years ago, three American scientists set their sights on a seemingly impossible goal: Sending pulses of light down a hair-thin strand of glass to form strong, reliable communications signals.
When they succeeded – with the unlikely help of an ordinary vacuum cleaner – the inventors harnessed the power of light and set in motion the modern optical communications revolution.
It’s hard to imagine today’s world without optical fiber — a thin but powerful glass strand that enables voice, data, and video information in the form of light signals that maintain their strength over long distances at very high speeds. More than two billion kilometers of optical fiber around the world form the backbone of today’s advanced telecommunication networks.
But in the late 1960s, most communications networks were based on copper wire, which transmitted signals electrically. Problem was copper networks were severely limited in both bandwidth and reach for the growing communications needs of contemporary business.
Shifting from electrical to optical transmission looked intriguing, but early optical fibers couldn’t transmit light signals over long distances without significant attenuation, or loss of signal strength.
That began to change in 1965, when the British Post Office developed a visionary plan to modernize its communications infrastructure. Post Office leaders turned to Corning Glass Works (now Corning Incorporated) – already a noted leader in specialty glass innovations – to develop a low-loss optical fiber.
To meet their goals, Post Office officials weren’t looking for any modest fiber improvements. They would need an unheard-of 98% reduction in signal attenuation from other glass fibers available at the time.
Corning formed a small multi-disciplinary team of Ph.Ds to take on the daunting task: physicist Robert Maurer, chemist Peter Shultz, and physicist Don Keck. Maurer led and coordinated the effort. Shultz was in charge of glass composition. And Keck was in charge of actually measuring the light transmission and attenuation.
Those light measurements were crucial to the success of the project, noted Maurer: “You don’t get anywhere unless you can really measure what you’re doing.”
The scientists collaborated closely, each attacking the challenge from different points of view.
“We progressed step by step; everybody at first handling their end of it, but gradually the team came together and we could interact and became more coherent,” Maurer recalled. “But it was just a series of experiments – changing this, changing that, and measuring what the result was.”
As with all experiments, there were many trials, many setbacks, and many late nights in the lab.
One of the biggest challenges was finding the right glass encasement, or cladding, for the fiber. Essential because its low refractive index confines light to the core of the fiber, the cladding needed to be thin, flexible and inch-for-inch stronger than steel.
That’s where the vacuum cleaner comes in. The team had an idea to use a regular vacuum cleaner to capture some of the soot generated by the high-temperature manufacturing process into a cladding tube.
Here’s how Shultz describes their process:
The way we sucked that (dopant) in was to hook an old vacuum cleaner … We basically drew the soot out of the flame into the cladding tube, and it deposited on the inside wall. Then we took that, put it in a furnace, heated it up, and the glass would sinter (deposit and fuse) on the inside wall. … That really solved very quickly the problems of scattering and losses due to the interface.
This approach worked. And by doping the silica glass core with titanium, the inventors reached a breakthrough that came late on a Friday afternoon.
Keck was in the laboratory testing this new optical fiber with a focused laser beam. He remembers:
I lifted my head up and saw this wonderful, bright single-mode pattern on the card that I had at the output end of the fiber. I knew something was dramatically different from any fiber that we’d seen before.
When he made the measurement, the reduction in attenuation was only 17 decibels per kilometer – loss levels even lower than the 98% reduction goal the British Post Office needed.
“Whoopee!” he jotted in his formula-filled lab notebook.
Most of his colleagues had already left for the weekend, but Keck was eager to share his news. His hallway search led him to Dr. William Armistead, the head of research at Sullivan Park, and he issued an invitation in the form of the ultimate understatement: “Do you want to see something neat?”
The breakthrough innovation immediately established that optical communications could be practical. Within several years – using germanium oxide as the core dopant – Corning produced a fiber with attenuation of only 4 decibels per kilometer.
The 1970 discovery by Maurer, Schultz, and Keck continues to fascinate historians and scientists alike. Their work paints a picture of materials science research at its best: An enormously complex problem solved with bold experimentation, uncompromising attention to detail, and deep understanding of the fundamentals.
It also forms a compelling human story of confidence, creativity, and teamwork that resulted in technology to harness light and shape communications around the world.
Claudio Mazzali is Senior Vice President, Technology, Corning Optical Communications and Optical Connectivity Solutions. In this role Claudio expanded his previous responsibility, acting now as the chief technology officer for the COC sector while still responsible for the technology development for the OCS division. Previously Mazzali was the business technology director for the Telecom Sector, leading its early stage development by leveraging a close connection with the Research organization and focusing on integrated solutions that require collaboration between fiber, cables, and connectivity.
Mazzali joined Corning in 1999 at the Brazilian regional office as an optical communications specialist, and later became technical manager for Corning Optical Fiber in Latin America. In 2001, Mazzali was transferred to Corning, N.Y., and has held multiple positions in Corning Optical Fiber, including strategic alliances manager, product line manager for high-data-rate and submarine products, and new business development manager.
Mazzali holds a Ph.D. in physics from the Gleb Wataghin Physics Institute at Unicamp, Brazil. He is a member of the Optical Society of America, and the current Chairman of the Optoelectronics Industry Development Association (OIDA) Board of Directors.