Sand from centuries past; Send future voices fast. 古沙递捷音
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A Nobel Lecture organized by the Royal Swedish Academy of Sciences and The Prize Committee in Physics delivered by Mrs Gwen MW Kao on behalf of Prof Charles K Kao Nobel Laureate in Physics 2009 8 December 2009 Aula Magna Stockholm University
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1. Introduction
m! x, H- ]7 V, l) y4 DIt is sad that my husband, Professor Charles Kao, is unable to give this lecture to you himself. As the person closest to him, I stand before you to honour him and to speak for him. He is very very proud of his achievements for which the Nobel Foundation honours him. As are we all!
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In the 43 years since his seminal paper of 1966 that gave birth to the ubiquitous glass fiber cables of today, the world of telephony has changed vastly. It is due to Professor Kao’s persistence in the face of skepticism that this revolution has occurred.
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In the 1970s the pre-production stage moved to ITT Corp Roanoke VA, USA. Whilst Charles worked there, he received two letters. One contained a threatening message accusing him of releasing an evil genie from its bottle; the other, from a farmer in China, asked for a means to allow him to pass a message to his distant wife to bring his lunch. Both letter writers saw a future that has since become past history.
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1。导言
9 S, U* H* h. H令人遗憾的是我的丈夫，高锟教授，是无法给你这个演讲自己。由于他最亲近的人，我站在你们面前，履行他和他说话。他非常非常自豪的成就为诺贝尔基金会的荣誉了。正如我们大家！
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在43年自他1966年开创性论文，催生无处不在的玻璃纤维电缆的今天，世界上的电话改变了巨大变化。正是由于高教授的坚持的怀疑，这场革命已经发生的脸。
# c1 X$ B- O% X0 e& \在20世纪70年代前生产阶段转移到弗吉尼亚州罗阿诺克公司ITT公司，美国。虽然查尔斯在那里工作，他收到两封信。一个载有威胁的消息，指责其释放1瓶邪恶精灵他，另一方面，从一个中国农民，一个手段，让他传递一个信息，他遥远的妻子把他的午餐问题。双方来信，看到了未来已经成为过去的历史。
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1 p: O+ |' N* ~ s$ ]1 Y. t% @In the 1960s, our children were small. Charles often came home later than normal – dinner was waiting as were the children. I got very annoyed when this happened day after day. His words,maybe not exactly remembered, were –‘Please don’t be so mad. It is very exciting what we are doing; it will shake the world one day!’ I was sarcastic, ‘Really, so you will get the Nobel Prize, won’t you!
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He was right – it has revolutionized telecommunications.
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在20世纪60年代，我们的孩子还小。查尔斯回家后往往比正常 - 晚餐等候，是儿童。我得到非常难看当天发生的这一天之后。他的话，也许不完全记住，是 - '请不要生气。这是非常令人兴奋的我们在做什么，它会动摇世界一天！'我是讽刺，'真的，所以你会得到诺贝尔奖，是不是！
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他是正确的 - 它彻底改变了电信。
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2. The early days
2 X* w0 l/ B: M0 k+ ]* FIn 1960, Charles joined Standard Telecommunications Laboratories Ltd. (STL), a subsidiary of ITT Corp in the UK, after having worked as a graduate engineer at Standard Telephones and Cables in Woolwich for some time. Much of the work at STL was devoted to improving the capabilities of the existing communication infrastructure with a focus on the use of millimeter wave transmission systems.
8 l) p2 G6 b* U" Y2。早期
6 T9 e w4 p, f1960年，查尔斯加入后，作为一个标准电话电缆在伍尔维奇毕业的工程师一段时间后标准电讯实验室有限公司（STL）的，公司的ITT公司在英国的子公司。对在STL的大部分工作是用于改善现有的通信基础设施的能力与对毫米波传输系统的使用重点。
# @( v8 v0 c/ z/ PMillimeter waves at 35 to 70 GHz could have a much higher transmission capacity. But the waters were uncharted and the challenges enormous, since radio waves at such frequencies could not be beamed over long distances due to beam divergence and atmospheric absorption. The waves had to be guided by a waveguide. And in the 1950’s, R&D work on low loss circular waveguides –HE-11 mode – was started. A trial system was deployed in the 1960s. Huge sums were invested, and more were planned, to move this system into the pre-production stage. Public expectation for new telecommunication services such as the video phone had heightened.
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在35毫米至70 GHz的海浪可能有更高的传输容量。但未知的水域和巨大的挑战，因为在这些无线电波的频率不能超过由于光束发散和吸收大气中长距离微笑。海浪必须由波导指导。而在1950年的低损失的，研发工作的通知波导，何- 11模式 - 已启动。一个试用系统部署在20世纪60年代。巨额的投资，更是有计划，迁入预生产阶段，该系统。公众对新的电信服务的期望，如可视电话加剧了。
1 l/ s9 L2 r+ D2 F: S4 sCharles joined the long-haul waveguide group led by Dr Karbowiak at STL. He was excited to see an actual circular waveguide. He was assigned to look for new transmission methods for microwave and optical transmission. He used both ray optics and wave theory to gain a better understanding of waveguide problems – then a novel idea. Later, his boss encouraged him to pursue a doctorate while working at STL. So Charles registered at University College London and completed the dissertation ‘Quasi-Optical Waveguides’ in two years.
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The invention of the laser in 1959 gave the telecom community a great dose of optimism that optical communication could be just around the corner. The coherent light was to be the new information carrier with capacity a hundred thousand times higher than point-to-point microwaves –based on the simple comparison of frequencies: 300 terahertz for light versus 3 gigahertz for microwaves.
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The race between circular microwave waveguides and optical communication was on, with the odds heavily in favour of the former. In 1960, optical lasers were in their infancy, demonstrated at only a few research laboratories, and performing much below the needed specs. Optical systems seemed a non-starter.
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0 [' |0 ~# F$ P' jBut Charles still thought the laser had potential. He said to himself: ‘How can we dismiss the laser so readily? Optical communication is too good to be left on the theoretical shelf.’
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+ g7 S# @: a; e2 o5 pHe asked himself the obvious questions:
4 W2 w6 o3 U$ s! D0 ~: R1. Is the ruby laser a suitable source for optical communication?
7 G* x! h1 M g4 r, I! f2. What material has sufficiently high transparency at such wavelengths?
1 L' n8 }4 C# m" b" {8 JAt that time only two groups in the world were starting to look at the transmission aspect of optical communication, while several other groups were working on solid state and semiconductor lasers. Lasers emit coherent radiation at optical frequencies, but using such radiation for communication appeared to be very difficult, if not impossible. For optical communication to fulfill its promises, many serious problems remained to be solved.
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% n/ b$ u. [% J I: f; j3 \; f3. The key discovery
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In 1963 Charles was already involved in free space propagation experiments: the rapid progress of semiconductor and laser technology had opened up a broader scope to explore optical communication realistically. With a helium-neon laser beam directed to a spot some distance away, the STL team quickly discovered that distant laser light flickered. The beam danced around several beam diameters because of atmospheric fluctuations.
! J: S. l* d4 l8 M+ A' J) x; YThe team also tried to repeat experiments done by other research laboratories around the world. For example, they set up con-focal lens experiments similar to those at Bell Labs: a series of convex lenses were lined up at intervals equal to the focal length. But even at the dead of night when the air was still and even with refocusing every 100 meters, the beam refused to stay within the lens aperture.
* G* V' h) X$ k: tBell Labs experiments using gas lenses were abandoned due to the difficulty of providing satisfactory insulation while maintaining the profiles of the gas lenses. These experiments were struggles in desperation, to control light travelling over long distances.
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At STL the thinking shifted towards dielectric waveguides. Dielectric means a non-conductor of electricity; a dielectric waveguide is a waveguide consisting of a dielectric cylinder surrounded by air. Dr Karbowiak suggested Charles and three others to work on his idea of a thin film waveguide.
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But thin film waveguides failed: the confinement was not strong enough and light would escape as it negotiates a bend.
! `) V& f0 P, _7 K( ^7 Y) d4 }, fWhen Dr Karbowiak decided to emigrate to Australia, Charles took over as the project leader and he then recommended that the team should investigate the loss mechanism of dielectric materials for optical fibers.
?9 h# h/ K' t. G' ?A small group worked on methods for measuring material loss of low-loss transparent materials. George Hockham joined him to work on the characteristics of dielectric waveguides.
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With his interest in waveguide theory, he focused on the tolerance requirements for an optical fiber waveguide; in particular, the dimensional tolerance and joint losses. They proceeded to systematically study the physical and waveguide requirements on glass fibers.
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In addition, Charles was also pushing his colleagues in the laser group to work towards a semiconductor laser in the near infrared, with emission characteristics matching the diameter of a single-mode fiber. Single mode fiber is optical fiber that is designed for the transmission of a single ray or mode of light as a carrier. The laser had to be made durable, and to work at room temperatures without liquid nitrogen cooling. So there were many obstacles. But in the early 1960s,
9 D- K8 O- P/ |$ l( yesoteric research was tolerated so long as it was not too costly.
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Over the next two years, the team worked towards the goals. They were all novices in the physics and chemistry of materials and in tackling new electromagnetic wave problems. But they made very credible progress in considered steps. They searched the literature, talked to experts, and collected material samples from various glass and polymer companies. They also worked on the theories, and developed measurement techniques to carry out a host of experiments. They developed an instrument to measure the spectral loss of very low-loss material, as well as one for scaled simulation experiments to measure fiber loss due to mechanical imperfections.
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Charles zeroed in on glass as a possible transparent material. Glass is made from silica –sand from centuries past that is plentiful and cheap.
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The optical loss of transparent material is due to three mechanisms: (a) intrinsic absorption, (b)extrinsic absorption, and (c) Rayleigh scattering. The intrinsic loss is caused by the infrared absorption of the material structure itself, which determines the wavelength of the transparency
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regions. The extrinsic loss is due to impurity ions left in the material and the Rayleigh loss is due to the scattering of photons by the structural non-uniformity of the material. For most practical applications such as windows, the transparency of glass was entirely adequate, and no one had studied absorption down to such levels. After talking with many people, Charles eventually formed the following conclusions.
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1. Impurities, particularly transition elements such as iron, copper, and manganese, have to be reduced to parts per million or even parts per billion. However, can impurity concentrations be reduced to such low levels?
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2. High temperature glasses are frozen rapidly and therefore are more homogeneous, leading to a lower scattering loss.
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The ongoing microwave simulation experiments were also completed. The characteristics of the dielectric waveguide were fully defined in terms of its modes, its dimensional tolerance both for end-to-end mismatch and for its diameter fluctuation along the fiber lengths. Both the theory and the simulated experiments supported the approach.
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They wrote the paper entitled, ‘Dielectric-Fibre Surface Waveguides for Optical Frequencies’ and submitted it to the Proceedings of Institute of Electrical Engineers. After the usual review and revision, it appeared in July 1966 – the date now regarded as the birthday of optical fiber communication.
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4. The paper
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The paper started with a brief discussion of the mode properties in a fiber of circular cross section.
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The paper then quickly zeroed in on the material aspects, which were recognized to be the major stumbling block. At the time, the most transparent glass had a loss of 200 dB/km, which would limit transmission to about a few meters – this is very obvious to anyone who has ever peered through a thick piece of glass. Nothing can be seen.
( N% ]% S5 b7 ?4 [6 hBut the paper pointed out that the intrinsic loss due to scattering could be as low as 1 dB/km,which would have allowed propagation over practical distances. The culprit is the impurities:
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mainly ferrous and ferric ions at these wavelengths. Quoting from the paper: ‘It is foreseeable that glasses with a bulk loss of about 20 dB/km at around 0.6 micron will be obtained, as the iron-impurity concentration may be reduced to 1 part per million’. In layman terms, if one has a sufficiently ‘clean’ type of glass, one should be able to see through a slab as thick as several hundred meters. That key insight opened up the field of optical communications.
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The paper considered many other issues:
! E# [" B# P3 C* Z, n( \? The loss can be reduced if the mode is chosen so that most of the energy is actually outside the fiber.
+ _; G* i! {4 W6 B. ^6 a- a? The fiber should be surrounded by a cladding of lower index (which became the standard technology).
. S" j3 q" a, g" B1 h; i) G? The loss of energy due to bends in the fiber is negligible for bends larger than 1 mm.
) g5 h3 t4 e- W. I4 C7 }3 |? The losses due to non-uniform cross sections were estimated.
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? The properties of a single-mode fiber (now a key technology especially for long distance and high data rate transmission) were analyzed. It was explained how dispersion limits bandwidth; an example was worked out for a 10 km route – a very bold scenario in 1966.
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0 i% a4 W( s# B) j5 E# g2 SIt may be appropriate to quote from the Conclusion of this paper:
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The realization of a successful fiber waveguide depends, at present, on the availability of suitable low-loss dielectric material. The crucial material problem appears to be one which is difficult but not
' n. `- |2 g8 Z4 rimpossible to solve. Certainly, the required loss figure of around 20 dB/km is much higher than the lower limit of loss figure imposed by fundamental mechanisms.
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Basically all of the predictions pointed accurately to the paths of developments, and we now have 1/100 of the loss and 10,000 times the bandwidth then forecast – the evolutionary proposal in the 1966 paper was in hindsight too conservative.
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$ E# T) Z+ h7 s, ]+ \1 I5. Convincing the world
$ p, i$ Q; z) ?$ zThe substance of the paper was presented by Dr Kao at an IEE meeting in February 1966. Most of the world did not take notice – except for the British Post Office (BPO) and the UK Ministry of Defense, who immediately launched major research programs. By the end of 1966, three groups in the UK were studying the various issues involved: Kao himself at STL; Roberts at BPO; Gambling at Southampton in collaboration with Williams at the Ministry of Defense Laboratory.
+ `5 n- H$ h! q: W# Y2 bIn the next few years, Dr Kao traveled the globe to push his idea: to Japan, where enduring friendships were made dating from those early days; to research labs in Germany, in the Netherlands and elsewhere to spread his news. He said that until more and more jumped on the bandwagon, the use of glass fibers would not take off. He had tremendous conviction in the face of widespread skepticism. The global telephony industry is huge, too large to be changed by a single person or even a single country, but he was persistent and his enthusiasm was contagious, and slowly he converted others to be believers.
% s5 ?% \) V% S5 p" _5 v1 l& uThe experts at first proclaimed that the materials were the most severe of the intrinsic insurmountable problems. Gambling wrote that British Telecom had been ‘somewhat scathing’about the proposal earlier, and Bell Labs, who could easily have led the field, simply failed to take notice until the proven technology was pointed out to them. Dr Kao visited many glass manufacturers to persuade them to produce the clear glass required. He got a response from Corning, where Maurer led the first group that later produced the glass rods and developed the
3 W7 Z: i; z4 C: K0 ]% d, btechniques to make the glass fibers to the required specifications.
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Meanwhile, Dr Kao continued to pour energy into proving the feasibility of glass fibers as the medium for long-haul optical transmission. They faced a number of formidable challenges. The first was the measurement techniques for low-loss samples that were obtainable only in lengths of around 20 cm. The problem of assuring surface perfection was also ormidable. Another problem is end surface reflection loss, caused by the polishing process. They faced a measurement impasse that demanded the detection of a loss difference between two samples of less than 0.1%, when the total loss of the entire 20 cm sample is only 0.1%. An inexact measurement would be meaningless.
/ e3 G# m m2 a6 A7 n5 {( d6 ]In 1968 and 1969, Dr Kao and his colleagues Davies, Jones and Wright at STL published a series of papers on the attenuation measurements of glass that addressed the above problems. At that time, the measuring instruments called spectrophotometers had a rather limited sensitivity – in the range of 43 dB/km. The measurement was very difficult: even a minute contamination could have caused a loss comparable to the attenuation itself, while surface effects could easily be ten times worse. Dr Kao and the team assembled a homemade single-beam spectrophotometer that achieved a sensitivity of 21.7 dB/km. Later improvements with a double-beam spectrophotometer yielded a sensitivity down to 4.3 dB/km.
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The reflection effect was measured with a homemade ellipsometer. To make it, they used fused quartz samples made by plasma deposition, in which the high temperature evaporated the impurity ions. With the sensitive instrument, the attenuation of a number of glass samples was measured and, eureka, the Infrasil sample from Schott Glass showed an attenuation as low as 5 dB/km at a window around 0.85 micron – at last proving that the removal of impurity would lower the absorption loss to useful levels.
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This was really exciting because the low-loss region is right at the gallium-arsenide laser emission band. The measurements clearly pointed the way to optical communication –compact gallium-arsenide semiconductor lasers as the source, low-cost cladded glass fibers as the transmission medium, and silicon or germanium semiconductors for detection. The dream no longer seemed remote. These measurements apparently turned the sentiments of the research community around. The race to develop the first low-loss glass fiber waveguide was on.
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, c- n9 B4 ^' G1 ]6 x1 HIn 1967, at Corning, Maurer’s chemist colleague Schultz helped to purify the glass.
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In 1968, his colleagues Keck and Zimar helped to draw the fibers. By 1970, Corning had produced a fiber waveguide with a loss of 17 dB/km at 0.633 micron using a titanium-diffused core with silica cladding, using the Outside Vapor Deposition (OVD) method. Two years later, they reduced the loss to 4 dB/km for a multimode fiber by replacing the titanium-doped core with a germanium-doped core.
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Bell Labs finally got on the bandwagon in 1969 and created a programme in optical fiber research after having been skeptical for years. Their work on hollow light pipes was finally stopped in 1972. Their millimeter wave research programme was wound down and eventually abandoned in 1975.
. J5 C+ R3 M( r6 T( t j& ^+ Y6 AIt was during this time of constant flying out to other places that this cartoon joke hit home:‘Children, the man you see at the breakfast table today is your father!’
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We saw him for a few days and off he went again. Sometimes he flew off for the day for meetings at ITT Corp headquarters in New York. I would forget he had not left to go to the office and would phone his secretary to remind Charles to pick up milk or something on his way home.
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His secretary was very amused:‘Mrs Kao, don’t you know your husband is in New York today!’
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- C& Z5 \$ h' v) y, A, ?5 @6. Impact on the world
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Since the deployment of the first-generation, 45-megabit-per-second fiber-optic communication system in 1976, the transmission capacity in a single fiber has rapidly increased a million fold to tens of terabits per second. Data can be carried over millions of km of fibers without going through repeaters, thanks to the invention of the optical fiber amplifier and wavelength division multiplexing. So that is how the industry grew and grew. The world has been totally transformed because of optical fiber communication. The telephone system has been overhauled and international long distance calls have become easily affordable.
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Brand new mega-industries in fiber optics including cable manufacturing and equipment, optical devices, network system and equipment have been created.
5 \' @7 b' L: F: O9 y4 t3 t. UHundreds of millions of kilometers of glass fiber cables have been laid, in the ground and in the ocean, creating an intricate web of connectivity that is the foundation of the world-wide web.
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The Internet is now more pervasive than the telephone used to be. We browse, we skype, we blog, we go onto you-tube, we shop, we socialize on-line. The information revolution that started in the 1990s could not have happened without optical fibers.
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Over the last few years fibers are being laid all the way to our homes. All-optical networks that are environmentally green are contemplated. The revolution in optical fiber communication has not ended – it might still just be at the beginning.
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7. Conclusion
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The world-wide communication network based on optical fibers has truly shrunk the world and brought human beings closer together. I hardly need to cite technical figures to drive this point home. The news of the Nobel Prize reached us in the middle of the night at 3 am in California, through a telephone call from Stockholm (then in their morning) no doubt carried on optical fibers; congratulations came literally minutes later from friends in Asia (for whom it was evening), again through messages carried on optical fibers. Too much information is not always a good thing: we had to take the phone off the hook that night in order to get some sleep!
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Optical communication is by now not just a technical advance, but has also caused major changes in society. The next generation will learn and grow up differently; people will relate to one another in different ways. Manufacturing of all the bits and pieces of a single product can now take place over a dozen locations around the world, providing huge opportunities for people especially in developing countries. The wide accessibility of information has obviously led to more equality and wider participation in public affairs.
3 J$ C; u: E( i# b- W+ g. \Many words, indeed many books have been written about the information society, and I do not wish to add to them here – except to say that it is beyond the dreams of the first serious concept of optical communication in 1966, when even 1 GHz was only a hope.
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In conclusion, Charles and I want to thank the Professors at The Chinese University of Hong Kong, namely: Professor Young, Professor Wong, Professor Cheung and Professor Chen for their support in compiling this lecture for us. Charles would like to thank ITT Corp where he developed his career for 30 years and all those who climbed on to the bandwagon with him in the early days, as without the legions of believers the industry would not have evolved as it did.
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Charles Kao planted the seed; Bob Maurer watered it and John MacChesney grew its roots.
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查尔斯加入长途波导集团Karbowiak博士领导的STL的。他很兴奋地看到实际的圆波导。他被分配到寻求对微波和光传输的新传输方法。他利用射线光学和波理论，以取得对波导问题，更好地理解 - 那么一个崭新的概念。后来，他的老板鼓励他攻读博士学位，而在STL的工作。因此，查尔斯登记伦敦大学学院，并完成光波导'在两年论文'准。
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激光的发明，让1959年的电信社会，光通信的可指日可待剂量非常乐观。相干光灯是为能与能力的新的信息载体十万倍百分点点对点微波，基于频率简单的比较：300赫兹的微波为3千兆赫。
# Y# z8 q% I+ d6 d7 q% J微波之间的圆形波导和光通信的比赛，与前赞成的可能性严重。 1960年，光纤激光器在萌芽状态，只有少数研究实验室证明，并大大低于所需的规格执行。光学系统似乎是一个非首发。
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( v2 \3 x* ]4 P1 x+ m4 |) e( @4 T但查尔斯仍然认为，用激光潜力。他对自己说：'我们怎样才能排除激光那么容易？光通信是好得货架上左边的理论。
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- C, S8 ~& i; k$ M' `) Y* W5 i他问自己明显的问题：
/ K' W8 P4 q2 U2 G1。红宝石激光是一种光通信合适的来源？
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2。什么材料具有相当高的透明度，在这种波长？
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当时只有两个在世界组开始看光通信传输方面，而其他几个组，对固体和半导体激光器工作。激光器发出的光的频率相干辐射，但使用这种辐射的沟通似乎是非常困难的，如果不是不可能的。对于光通信履行自己的诺言，许多严重的问题有待解决。
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3。关键发现
; \0 e3 I* O6 B) |; j- s1963年查尔斯已经参与了自由空间传输实验：半导体和激光技术在更大范围内建立一个开放，探索现实光通信的迅速发展。随着氦氖激光束定向到一些实地的距离，STL的团队很快发现，遥远的激光闪烁。因为周围的大气波动的几束的光束直径跳舞。
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该小组还试图重复世界上其他实验室进行实验研究。例如，他们成立了节能焦距镜头类似的实验，在贝尔实验室的：一凸系列镜头在排队的时间间隔等于焦距了。但是，即便在深夜时，空气中仍然和重新定位，甚至每100米，梁拒绝留在镜头光圈。
+ v% t3 @! i% n( @. H1 g3 o* ^贝尔实验室的实验用气镜头被遗弃由于难以提供满意的同时保持绝缘的气体镜头的配置文件。这些试验是在绝望的斗争，以控制光长途旅行。
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在STL的思想转向介质波导。介指非电导体，电介质波导波导，航空包围的介质圆柱组成。查尔斯博士Karbowiak建议，3人在他工作的薄膜波导的想法。
# T9 U& y; [( J; |: I0 [但是薄膜波导失败：隔离并没有强大到足以和轻，因为它会逃跑谈判一个弯。
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当医生Karbowiak决定移居澳洲，查尔斯接任该项目负责人，他便建议小组应调查的光纤介质材料损失的机制。
) e) l9 F5 m% [/ Z* [6 j* U- Q一小群的方法测量工作，物质损失的低损耗透明材料。乔治Hockham他一起工作的介质波导的特点。
, J1 c$ P2 I6 p2 t" m- M由于他在波导理论的兴趣，他重点是光纤波导的公差要求，特别是尺寸公差和联合的损失。他们着手有系统地研究玻璃纤维的物理和波导的要求。
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此外，查尔斯也推动了激光组他的同事们努力建立一个半导体激光在近红外，与排放特性匹配的单模光纤的直径。单模光纤是光纤是为单一射线或作为承运人的光传输模式设计的。激光必须作出持久的，并没有工作液氮冷却室温。因此，有许多障碍。但在60年代初，
; A1 l* Y) h9 ?( n! B( _2 ?深奥的研究是不能容忍的，只要它是不是太昂贵。
" M" E* L. @: w- j; W% z在未来两年内，车队实现目标。他们是在物理和材料化学和解决新问题的电磁波新手。但是，他们提出了非常可靠的考虑采取的进展。他们搜查了文学，谈专家，并收集的材料样本各种玻璃和聚合物公司。他们还致力于理论，发展了测量技术进行实验主机。他们开发了一个工具来衡量的损失非常低光谱损耗材料，以及一个规模模拟实验来测量光纤损耗因机械缺陷。
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查尔斯对准玻璃作为一种可能的透明材料。玻璃是由硅，从过去几个世纪的充足和便宜的沙子。
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在光学透明材料损失是由于三种机制：（1）内在的吸收，（二）外在的吸收，以及（c）瑞利散射。内在的损失是由于材料的结构本身，它决定了透明度红外吸收波长
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地区。外在损失是由于杂质离子在物质左边，瑞利损失是由于光子的散射结构的非均匀性的材料。如窗户最实际的应用中，玻璃是完全足够的透明度，也没有人研究了吸收到这种程度。在与很多人交谈，查尔斯最终形成了以下结论。
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& N/ D* t, l, ^% s! Z& H1。杂质，特别是过渡元素铁，铜等，及锰，要减少到每百万甚至十亿分之几部分。但是，可以杂质浓度降低到如此低的水平？
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2。高温眼镜迅速冻结，因此更均匀，从而导致较低的散射损耗。
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正在进行的微波模拟试验也已完成。该介质波导的特点得到充分界定的方式上，它的尺寸公差为最终都到终端配合的，其纤维长度沿直径波动。理论和模拟实验支持的办法。
l8 Z& h5 n( C( f他们写了一篇题为'介质纤维表面波导光学频率'，并提交给了英国电气工程师学会学报。经过通常的审查和修订，它出现在1966年7月 - 现在作为光纤通信生日视为日期。
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4。该文件
/ y5 |3 u( g+ `2 y& y本文开始时，在一圆截面纤维的模式属性简短的讨论。
8 {" c3 A: L2 y0 d# t% |9 G! }# x该文件，然后迅速将目光聚集在各方面的材料，它被公认是主要的绊脚石。当时，最透明的玻璃有损失的二○○分贝/公里，这将限制了传输约数米 - 这是非常明显的人谁过通过一块厚玻璃窥视。什么也看不见。
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但该报指出，由于固有的散射损失可高达1分贝低/公里，这将在实际的传播距离允许的。罪魁祸首是杂质：
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在这些波长主要是有色金属和铁离子。引述该文件：'可以预见，约20分贝的大部分损失眼镜/公里0.6微米左右便可得到的铁杂质含量，可减少到1部分每100万'。一般用语，如果有足够的'干净'的玻璃种类，应该可以看到，通过一厚几百米板。这关键的见解开辟了光通信领域。
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g- [! D, e- {" |( v2 q该文件考虑许多其他问题：
7 [: b. G y4 ^) r6 v% Z？的损失可以减少，如果模式选择，使大多数的能量实际上是外纤维。
7 K* R q5 |6 Y3 F？该纤维应该包围着较低的指数熔覆（后来成为标准的技术）。
3 U. t+ G- d* H" g？能源在光纤由于弯损失是微不足道的弯曲大于1毫米。
& D4 |. P3 i$ ^# e' a？这些损失由于非均匀截面进行了估计。
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？在单模光纤性能的长途和高速率数据传输（现在的关键技术，特别是）进行了分析。有人解释如何分散限制带宽;一个例子是，制定了10公里的路线 - 在1966年一个非常大胆的设想。
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这也许是适当的引用本文件的结论：
X3 @% R9 f( g0 v" Z: n& ]# q( F" x一个成功的实现取决于光纤波导，目前，在合适的低损耗电介质材料的可用性。关键材料的问题似乎是一个是困难，但不是
8 T0 l- F) T8 p( h2 V就不可能解决。当然，需要约20分贝的损失数字/公里远高于规定的基本机制的损失数字的下限。
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( Y. Z7 k/ V( P! u3 v基本上所有的预测准确地指出了发展的道路，我们现在有1 /损失000倍的带宽，然后预测 - 1966年，在100文件的进化建议在事后过于保守。
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5。说服世界
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该文件的内容已提交会议的独立外部评价1966年2月高博士。世界上大多数没有理会 - 除英国邮政局（BPO）和国防部，谁立即展开大规模的研究计划，英国国防部。到1966年，三个组末英国研究涉及的各种问题：自己的STL的高;罗伯茨在业务流程外包;赌博与协作南安普敦威廉姆斯在国防实验室部。
+ Y0 t. e4 f( h$ x& P在未来几年，高博士前往世界各地，把他的想法：对日本，提出了持久的友谊，从当年约会;在研究实验室在德国，荷兰和其他地方传播他的消息。他说，直到越来越多地赶上，玻璃纤维的使用将不会起飞。他在普遍怀疑面临巨大的信念。全球通讯行业是巨大的，太大，无法由一个人或一个国家，甚至改变了，但他坚持不懈，他的热情是传染性的，他慢慢地转换成另一些被信徒。
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在第一次专家宣称，这些材料的内在无法克服的问题最为严重。赌博说，英国电信已经'有点scathing'about早些时候的建议，以及贝尔实验室，谁可以很容易导致外地，根本没有考虑到成熟技术通知向他们指出。高博士访问了许多玻璃制造商，说服他们生产所需的透明玻璃。他得到了康宁，其中毛雷尔领导的第一批后产生的玻璃棒和发展的反应
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技术，以玻璃纤维所需的规格。
9 e1 v7 v f# R+ R8 B) f同时，高博士继续涌入证明作为长期在玻璃纤维中的可行性长距离光传输能量。他们面临着严峻的挑战。首先是低损失样品的测量技术，只有在20厘米左右长度索取。在确保表面完美的问题也ormidable。另一个问题是端面反射损失，由抛光过程造成的。他们面临的僵局的测量要求的两批不到0.1％，损失分别检测样品时，整个20厘米样本总损失率仅为0.1％。一个不准确的测量将毫无意义。
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在1968年和1969年，高博士和他的同事在STL的戴维斯，琼斯和赖特出版了玻璃的衰减测量，解决上述问题的系列文件。当时，测量仪器称为分光光度计是相当有限的敏感性 - 在43分贝范围/公里。测量是很困难的：即使一分钟污染可能造成的损失相当于衰减本身，而表面效应很容易坏十倍。高博士和团队组建了一个自制的单光束分光光度计是实现了21.7分贝灵敏度/公里。以双光束分光光度计后来的改善产生了4.3分贝/公里的敏感性下降。
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反射效果的测量与自制椭。为了它，他们用熔融等离子体沉积，其中高温蒸发的杂质离子作出石英样品。随着敏感的工具，玻璃样品的数量是衡量和衰减，尤里卡，由肖特玻璃Infrasil抽样调查表明，作为一个5分贝低衰减/公里窗口周围0.85微米终于证明 - 这是除杂将吸收损失降低到有用的水平。
' t6 f! O* v7 x! J$ J! k这真是令人兴奋，因为低损耗地区是正确的砷化镓激光发射带。明确指出了测量的方法，光通信，紧凑镓作为源，低成本作为传输介质包覆玻璃纤维砷半导体激光器，硅或锗半导体检测。这个梦似乎不再遥远。显然，这些测量结果的研究社区周围的情绪。这场比赛的第一个开发低损耗玻璃纤维波导于。
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- R5 Q' g2 ~( I* A' _$ h; ^9 K1967年，康宁，毛雷尔的化学家同事舒尔茨有助于净化玻璃。
8 R v! V& P: h, g$ {+ z1968年，他的同事凯克和Zimar有助于引起纤维。到1970年，康宁公司已经生产了0.633微米一个拥有17分贝的损耗光纤波导/公里使用钛金属与硅包层扩散的核心，利用外部汽相沉积（气相沉积）方法。两年后，他们的损失减少到4分贝/多模光纤为取代用锗掺杂核心掺钛芯公里。
$ c% A6 f, V, C$ G1 C: Z: }4 Z贝尔实验室终于在1969年行列，创造了在光纤研究方案后，多年来一直持怀疑态度。鉴于它们对空心管的工作，终于在1972年停止。他们的毫米波的研究方案，平息，并最终在1975年放弃。
8 d: V8 S& y& r" X正是在这个不断飞往其他地方的时候，这个漫画笑话袭来：'孩子，你该名男子在早餐桌上今天是你父亲看到！
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我们看到了几天他和他又再次起飞。有时候，他飞走了，以供在ITT公司公司总部设在纽约开了一天。我会忘记他没有离开去办公室，将电话，提醒他的秘书查尔斯接回家途中牛奶或东西。
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9 d7 i9 I& D# y2 A他的秘书很开心：'杜高，你不知道你的丈夫是今天在纽约！
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6。对世界的影响
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自第一代部署，45兆位每秒的光纤通信系统在1976年，在单根光纤的传输容量急剧增加1万倍，达到每秒数十兆兆位。数据可以结转的纤维公里数百万人没有通过中继去，多亏了光纤放大器和波分复用的发明。所以这是怎样的产业越做越大。世界已经完全改变，因为光纤通信。该电话系统已检修和国际长途电话已经成为容易负担。
( l# T4 d+ X3 j& m; g全新的巨型包括光纤电缆制造和设备，光学设备，网络系统及设备等行业已经建立。
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对玻璃纤维电缆亿万公里，已经奠定，在地面和海洋，创造一种复杂的网络连接是世界万维网的基础。
+ o; n1 F$ ?- J互联网是目前比以往更为普遍的是电话。我们浏览，我们Skype公司，我们的博客，我们去到你管，我们店，我们社交网上。信息革命，在20世纪90年代开始不可能发生无光纤。
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在过去数年的纤维被解雇所有我们的家园的道路。全是绿色环保的光网络的设想。在光纤通信革命并没有结束 - 它可能还只是在开始。
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7。结论
" B9 Z. s4 x8 L& B4 s世界范围的通信网络，光纤为基础的，真正缩小了世界和人类带来的关系更加紧密。我几乎不需要举出技术的数字来把这一观点。在诺贝尔奖的消息传到上午3时，我们在加利福尼亚州，经历了一个从斯德哥尔摩打来的电话（当时在上午）对光纤进行毫无疑问，后来才写的祝贺来自亚洲的朋友分钟（在半夜谁是傍晚），再通过光纤进行的消息。太多的信息并不总是一件好事：我们不得不采取脱身的电话，晚上要睡觉！
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光通信是现在已不仅仅是一个技术进步，而且在社会上引起重大变化。下一代的学习和成长不同，人们会以不同的方式与彼此。所有的位和1件制造单一产品现在可以接管世界上十几个地点进行，特别在发展中国家人民巨大的机遇。广泛的信息获取显然导致更多的平等和更广泛地参与公共事务。
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许多话，确实有很多书，也有人写信息社会，我不想在此补充 - 除了说，它超越了第一次严重的光通信概念的梦想是在1966年，甚至是1千兆赫唯一的希望。
& D6 G5 W2 D0 a+ ^8 r1 }" |9 u$ e最后，查尔斯，我要感谢在香港，即中文大学教授：杨教授，王教授，张教授和陈教授他们在制订我们这个讲座的支持。查尔斯要感谢ITT公司公司开发的，他没有行业就不会发展了大批信徒的职业生涯30年，所有那些谁爬上早年与他的行列，因为它没有。
" ~0 L( h: @8 U: A高锟种植的种子;鲍勃毛雷尔浇水和约翰麦克切斯尼增长的根源。
批发网整理
