How Fiber Optics Was Invented -- The History of Fiber Optics from Bell's Photophone to Corning Researchers

Fiber optics is the contained transmission of light through long fiber rods of either glass or plastics. The light travels by process of internal reflection. The core medium of the rod or cable is more reflective than the material surrounding the core. That causes the light to keep being reflected back into the core where it can continue to travel down the fiber. Fiber optic cables are used for transmitting voice, images, and other data at close to the speed of light.

Who Invented Fiber Optics

Corning Glass researchers Robert Maurer, Donald Keck, and Peter Schultz invented fiber optic wire or "Optical Waveguide Fibers" (patent #3,711,262) capable of carrying 65,000 times more information than copper wire, through which information carried by a pattern of light waves could be decoded at a destination even a thousand miles away.

Fiber optic communication methods and materials invented by them opened the door to the commercialization of fiber optics. From long-distance telephone service to the Internet and medical devices such as the endoscope, fiber optics are now a major part of modern life.

Timeline

•     1854 - John Tyndall demonstrated to the Royal Society that light could be conducted through a curved stream of water, proving that a light signal could be bent.

•     1880 - Alexander Graham Bell invented his "Photophone," which transmitted a voice signal on a beam of light. Bell focused sunlight with a mirror and then talked into a mechanism that vibrated the mirror. At the receiving end, a detector picked up the vibrating beam and decoded it back into a voice the same way a phone did with electrical signals. However, many things—a cloudy day, for instance—could interfere with the Photophone, causing Bell to stop any further research with this invention.

•     1880 - William Wheeler invented a system of light pipes lined with a highly reflective coating that illuminated homes by using light from an electric arc lamp placed in the basement and directing the light around the home with the pipes.

•     1888 - The medical team of Roth and Reuss of Vienna used bent glass rods to illuminate body cavities.

•     1895 - French engineer Henry Saint-Rene designed a system of bent glass rods for guiding light images in an attempt at early television.

•     1898 - American David Smith applied for a patent on a bent glass rod device to be used as a surgical lamp.

•     1920s - Englishman John Logie Baird and American Clarence W. Hansell patented the idea of using arrays of transparent rods to transmit images for television and facsimiles respectively.

•     1930 - German medical student Heinrich Lamm was the first person to assemble a bundle of optical fibers to carry an image. Lamm's goal was to look inside inaccessible parts of the body. During his experiments, he reported transmitting the image of a light bulb. The image was of poor quality, however. His effort to file a patent was denied because of Hansell's British patent.

•     1954 - Dutch scientist Abraham Van Heel and British scientist Harold. H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers while Van Heel reported on simple bundles of clad fibers. He covered a bare fiber with a transparent cladding of a lower refractive index. This protected the fiber reflection surface from outside distortion and greatly reduced interference between fibers. At the time, the greatest obstacle to a viable use of fiber optics was in achieving the lowest signal (light) loss.

•     1961 - Elias Snitzer of American Optical published a theoretical description of single mode fibers, a fiber with a core so small it could carry light with only one wave-guide mode. Snitzer's idea was okay for a medical instrument looking inside the human, but the fiber had a light loss of one decibel per meter. Communications devices needed to operate over much longer distances and required a light loss of no more than 10 or 20 decibels (measurement of light) per kilometer.

•     1964 - A critical (and theoretical) specification was identified by Dr. C.K. Kao for long-range communication devices. The specification was 10 or 20 decibels of light loss per kilometer, which established the standard. Kao also illustrated the need for a purer form of glass to help reduce light loss.

•     1970 - One team of researchers began experimenting with fused silica, a material capable of extreme purity with a high melting point and a low refractive index. Corning Glass researchers Robert Maurer, Donald Keck and Peter Schultz invented fiber optic wire or "Optical Waveguide Fibers" (patent #3,711,262) capable of carrying 65,000 times more information than copper wire. This wire allowed for information carried by a pattern of light waves to be decoded at a destination even a thousand miles away. The team had solved the problems presented by Dr. Kao.

•     1975 - The United States government decided to link the computers at the NORAD headquarters at Cheyenne Mountain using fiber optics to reduce interference.

•     1977 - The first optical telephone communication system was installed about 1.5 miles under downtown Chicago. Each optical fiber carried the equivalent of 672 voice channels.

•     By the end of the century, more than 80 percent of the world's long-distance traffic was carried over optical fiber cables and 25 million kilometers of the cable. Maurer, Keck, and Schultz-designed cables have been installed worldwide.

Glass Fiber Optics at the US Army Signal Corp

The following information was submitted by Richard Sturzebecher. It was originally published in the Army Corp publication Monmouth Message.

In 1958, at the US Army Signal Corps Labs in Fort Monmouth New Jersey, the manager of Copper Cable and Wire hated the signal transmission problems caused by lightning and water. He encouraged Manager of Materials Research Sam DiVita to find a replacement for copper wire. Sam thought glass, fiber, and light signals might work, but the engineers who worked for Sam told him a glass fiber would break.

In September 1959, Sam DiVita asked 2nd Lt. Richard Sturzebecher if he knew how to write the formula for a glass fiber capable of transmitting light signals. DiVita had learned that Sturzebecher, who was attending the Signal School, had melted three triaxial glass systems using SiO2 for his 1958 senior thesis at Alfred University.

Sturzebecher knew the answer. While using a microscope to measure the index-of-refraction on SiO2 glasses, Richard developed a severe headache. The 60 percent and 70 percent SiO2 glass powders under the microscope allowed higher and higher amounts of brilliant white light to pass through the microscope slide and into his eyes. Remembering the headache and the brilliant white light from high SiO2 glass, Sturzebecher knew that the formula would be ultra pure SiO2. Sturzebecher also knew that Corning made high purity SiO2 powder by oxidizing pure SiCl4 into SiO2.

He suggested that DiVita use his power to award a federal contract to Corning to develop the fiber.

DiVita had already worked with Corning research people. But he had to make the idea public because all research laboratories had a right to bid on a federal contract. So in 1961 and 1962, the idea of using high purity SiO2 for a glass fiber to transmit light was made public information in a bid solicitation to all research laboratories. As expected, DiVita awarded the contract to Corning Glass Works in Corning, New York in 1962. Federal funding for glass fiber optics at Corning was about $1,000,000 between 1963 and 1970. Signal Corps Federal funding of many research programs on fiber optics continued until 1985, thereby seeding this industry and making today's multibillion dollar industry that eliminates copper wire in communications a reality.

DiVita continued to come to work daily at the US Army Signal Corps in his late 80's and volunteered as a consultant on nanoscience until his death at age 97 in 2010.

Source :thoughtco.com

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