HISTORICAL NOTE Reflecting on the Origins of Fiberoptic Communication "Imagine what .the keen minds of our resistance in accordance with the chang- fibers to communications. He proposed entertainment industry could do if they ing light. This, in turn, modulated the that a network of "light cables" could realized they had a hundred million amount of current going into a receiver. carry voice traffic. These cables, French channels into which they could funnel The result: a voice transmitted by light. conjectured, could be made of "a solid new and undreamed varieties of trash," The telephone changed the world and rod of glass or quartz, or a similar materi- wrote Isaac Asimov in 1962. The first the photophone did not because the pho- al, which has a low absorption coefficient working laser had been demonstrated tophone had a fatal flaw. A passing cloud for the wavelengths to be transmitted." just two years earlier and Asimov was could interrupt an act of communication The problem was that nobody could contemplating what the new optical tech- and bad weather muted the gadget alto- make a "light cable" in which light could nology might mean for communications. gether. Nothing short of enclosing the travel the length of a person, let alone the "Maybe we should stop right now," he beam of light could solve this problem. miles that would be necessary for a viable quipped. An initial move in that direction oc- communications network. No chance. The laser had inflamed the curred in 1854 when John Tyndall demon- Even in the 1950s, the prognosis was long-thwarted lust for optical communica- strated to a gathering of the Royal Society not looking good. Two internal reports at tions systems. Within a decade, research- how a bending stream of water could Bell Telephone Laboratories in 1945 and ers at Bell Telephone Laboratories, effectively trap light inside of it. He shined 1951, respectively, came up with pes- Corning Glass, and elsewhere had invent- a beam of light through a glass wall of a simistic outlooks. The materials for guid- ed the kinds of solid state lasers and pho- water-filled tank and on through a tube ing light were inadequate and the light todetectors and glass fibers needed to fitted into the opposite wall of the tank. sources available were not of the sort that build workable optical communications The light emerged as a white disk. But behaved well when confined. The pre- systems. In 1976, the first experimental when Tyndall opened a stopcock on the scient author of the earlier report, W.A. optical fiber links were going on-line in tube so that the water could spout out of Tyrell, even called for coherent light offices. Since then, the frenetic wiring of its end, something else happened. In his sources—lasers—13 years before Charles the world with high capacity optical fibers words, "the light upon reaching the limit- Townes and Arthur Schawlow published has even brought a portion of Asimov's ing surface of air and water was totally the theoretical paper that led by 1960 to nightmare to near reality. There could reflected and seemed to be washed down- the creation of the first working laser. well be a day in the near future when ward by the descending liquid, the latter The invention of the laser renewed inter- viewers will be able to choose from 500 being thereby caused to present a beauti- est around the world in optical communi- channels of trash. ful illuminated appearance." cation. Just as before, bad weather made But long before the laser was invented, This kind of total internal reflection, the air a bad medium even for laser-based sig- optical communication had racked up a very phenomenon that is the heart and nals. In the mid-1960s, Wheeler's notion of lineage. In the ancient world large torches soul of modern optical fibers, initially hollow reflective pipes was revived, this and sunlight reflectors served as optical inspired ideas in building design more time for communications applications signals that could be seen for miles. Flags readily than in communication technolo- instead of illuminating buildings. served similar purposes since ancient gy. In 1881, the year after Bell received his Researchers at Bell Telephone Laboratories times. In the 1790s, an optical telegraph photophone patent, William Wheeler, an built one version in which the pipes were using movable arms atop towers was engineer in Concord, Massachusetts, filled with gas and then locally heated to designed in France. In 1840, the Prussian applied for a patent for a system of hollow create a lensing effect that refocuses the General Joseph Jakob Baeyer suggested pipes with reflective interiors to distribute light along the pipe's length. that the heliotrope—an instrument that light from a central source throughout a Another nemesis was lying in wait to focuses sunlight into a narrow beam that building. His timing could have been bet- again cut down Wheeler's vision. Elias Karl Friedrich Gauss had invented twen- ter. The advent of incandescent lighting, Snitzer, who was then at American ty years earlier for making land measure- in which light is produced locally using Optical, proposed in 1963 that the connec- ments—could serve well for transmitting electricity, stranded Wheeler's idea into tion of lasers and optical fibers was the messages. British and American military the category of things easily forgotten. key to optical communications. He was forces used a variation on that theme, By 1930, several inventors in Britain right, of course, but his suggestion took a called a heliograph, as an alternative to and the United States helped to connect Panglossian act of optimism. Only one the electric telegraph. the transmission of light to glass fibers. percent of the light going into a one meter The inventor of the telephone himself, Their patents, which involved solid glass length of the best made glass fibers at the Alexander Graham Bell, filed a patent in or quartz fibers, had to do with transmit- time would emerge. Another meter's August of 1880, for a "photophone," ting images, not voices. One early appli- worth, and only one percent of one per- which he demonstrated between a couple cation of the idea was to use flexible cent of the original input emerged. After of rooftops along 14th Street in fibers for internal medical observations a kilometer, it was profound darkness. Washington, DC. A human voice caused a la gastroscopy. Grim as that seemed, two engineers at a thin mirror to vibrate. A beam of sun- In 1934, Norman French, an engineer at Standard Telecommunications Labora- light reflecting from that mirror onto a the American Telephone and Telegraph tories saw signs of hope. In an uplifting selenium pickup altered the pickup's Corporation, saw the relevance of such 1966 article they argued that the losses of

MRS BULLETIN/SEPTEMBER 1995 57 HISTORICAL NOTE

light traveling in glass fibers were due nications has become a society-changing Areas in Communications SAC-1 (April, largely to impurities in the glass and not technology. With them, information 1983) pp. 356-372; J.B. MacChesney, "The to some fundamental limitation. Get superhighways are paved. Materials Development of Optical Fibers: enough of the impurities out, they pre- A Case History," Journal of Materials IVAN AMATO dicted, and they would have the right Education 11 (1989) pp. 325-356; Ira stuff for optical fibers. Four years later, a FOR FURTHER READING: Sami Faltas, "The Magaziner and Mark Patinkin, The Silent group of glass researchers at Corning Invention of Fibre-Optic Communi- War: Inside the Global Business Battles Glass confirmed the prediction by mak- cations," History and Technology 5 (1988) Shaping America's Future (see chapter on ing the first glass fibers with sufficiently pp. 31-49; R. Kompfer, "Optics at Bell Corning Glass), Vintage Books (New York, low light loss. By this time, solid state sci- Laboratories—Optical Communications," 1989); "A Revolution of Light: The Inven- entists also had made headway in the Applied Optics 11 (November, 1972) pp. tion of Low-Loss Optical Fiber," a pam- kinds of lasers and detectors that would 2412-2425; Tingye Li, "Advances in phlet published by Corning Incorporated, have to be on the ends of optical fibers. A Optical Fiber Communications: An Histor- Opto Electronics Group. quarter of a century later, optical commu- ical Perspective," IEEE Journal on Selected

CONFERENCE REPORT

Ion-Beam Modification of Optics to Autos Treated at IBMM'95 The Ninth International Conference on nonsemiconductors, and novel ion-beam implantation to tune or isolate optical Ion Beam Modification of Materials equipment and techniques. devices and in forming optically active (IBMM'95), chaired by J.S. Williams of the The conference was organized into 15 centers and waveguides in semiconduc- Australian National University (ANU), oral sessions, including three plenary pre- tors (S. Coffa, Catania), polymers, and was held at ANU in Canberra, Australia, sentations covering areas of general inter- oxide ceramics (A. Polman, Amsterdam) from February 5-10, 1995. More than 300 est; 22 specialist invited papers and 51 was a major focus of several presentations participants attended the conference from contributed oral presentations; and three at the conference. The combined use of 33 countries. Over 420 abstracts were poster sessions. Several scientific high- ion-beam methods and more convention- accepted, and papers were delivered in lights covered a diverse spectrum of al means of growing and modifying either poster or oral sessions. The location materials and ion-beam processing meth- buried compounds and three-dimensional- of the conference contributed to a higher ods. These included both conventional layered structures featured prominently, than normal participation from Asia. and novel applications of ion beams such the main progress excellently reviewed in Scientists from 33 countries attended the as optical displays and optoelectronics, the plenary paper of S. Mantl, Julich. The conference, the highest participation com- motor vehicle and tooling parts, coatings formation of hard coatings by ion-assisted ing from Japan, followed by the United tailored for desired properties, studies of deposition or direct implantation (D. States, Germany, and Australia. In addi- fundamental defect properties, the pro- McKenzie, Sydney and J.C. Barbour, tion to IBMM'95, six informal supporting duction of novel (often buried) com- Sandia) was also an area which showed workshops, addressing key ion beam and pounds, and the treatment of biomedical much recent progress. Ion-beam tech- materials issues, were held at various materials. niques had also developed a pace, particu- locations both before and after the confer- The study of nanocrystals produced by larly those based on plasma immersion ence. The 30-50 participants attending ion implantation in a range of host matri- ion implantation or alternative techniques these workshops had ample time for dis- ces (plenary paper by H.H. Andersen, for large area surface treatment (such as cussion. The workshops were enjoyable Denmark), particularly for optoelectronics papers by J. Conrad, Wisconsin and I.G. and extremely stimulating, scientifically. applications (as indicated in a paper by Brown, Berkeley). Finally, the use of ion beams for the direct treatment of cancer- IBMM'95 covered traditional topics of H.A. Atwater, Caltech), was one especial- ous tissue (K.M. Horn, Sandia) was also a this conference series but highlighted ly new and exciting development. Despite particularly novel and interesting applica- areas of particular relevance to the several decades of study, major progress tion of ion beams. Australian research effort and areas that was reported at the conference in under- were internationally topical. Major topic standing defect evolution in semiconduc- In addition to several industrial sponsors areas included basic ion interactions, low tors and the role of defects in transient and the ANU, the Australian Materials energy processes, defects in semiconduc- impurity diffusion. A complete oral ses- Research Society and the International tors, high fluence implantation and phase sion was devoted to this topic, led by an Union of Materials Research Societies formation, applications in electronics and invited presentation from D.J. Eaglesham, (IUMRS) cosponsored the conference. optoelectronics, ion-beam modification of AT&T Bell Laboratories. The use of J.S. WILLIAMS

58 MRS BULLETIN/SEPTEMBER 1995