A bundle of silica glass fibers for optical communication, which are the de facto worldwide standard. Kao also first publicly suggested that silica glass of high purity is an ideal material for long range optical communication.
In the 1960s at Standard Telecommunication Laboratories (STL) based in Harlow, Essex, England, Kao and his coworkers did their pioneering work in creating fiber optics as a telecommunications medium, by demonstrating that the high-loss of existing fiber optics arose from impurities in the glass, rather than from an underlying problem with the technology itself.
In 1963, when Kao first joined the optical communications research team he made notes summarising the background situation and available technology at the time, and identifying the key individuals involved. Initially Kao worked in the team of Antoni E. Karbowiak (Toni Karbowiak), who was working under Alec Reeves to study optical waveguides for communications. Kao's task was to investigate fiber attenuation, for which he collected samples from different fiber manufacturers and also investigated the properties of bulk glasses carefully. Kao's study primarily convinced him that the impurities in material caused the high light losses of those fibers. Later that year, Kao was appointed head of the electro-optics research group at STL. He took over the optical communication program of STL in December 1964, because his supervisor, Karbowiak, left to take the Chair in Communications in the School of Electrical Engineering at the University of New South Wales (UNSW), Sydney, Australia.
Although Kao succeeded Karbowiak as manager of optical communications research, he immediately decided to abandon Karbowiak's plan (thin-film waveguide) and overall change research direction with his colleague George Hockham. They not only considered optical physics but also the material properties. The results were first presented by Kao to the IEE in January 1966 in London, and further published in July with George Hockham (1964–1965 worked with Kao).[a] This study first theorized and proposed to use glass fibers to implement optical communication, the ideas (especially structural features and materials) described are largely the basis of today's optical fiber communications.
"What Kao did in Harlow transformed the world and provided a backbone for the internet. He was the father of fiber optics."
In 1965,[b] Kao with Hockham concluded that the fundamental limitation for glass light attenuation is below 20 dB/km (decibels per kilometer, is a measure of the attenuation of a signal over a distance), which is a key threshold value for optical communications. However, at the time of this determination, optical fibers commonly exhibited light loss as high as 1,000 dB/km and even more. This conclusion opened the intense race to find low-loss materials and suitable fibres for reaching such criteria.
Kao, together with his new team (members including T. W. Davies, M. W. Jones, and C. R. Wright), pursued this goal by testing various materials. They precisely measured the attenuation of light with different wavelengths in glasses and other materials. During this period, Kao pointed out that the high purity of fused silica (SiO2) made it an ideal candidate for optical communication. Kao also stated that the impurity of glass material is the main cause for the dramatic decay of light transmission inside glass fiber, rather than fundamental physical effects such as scattering as many physicists thought at that time, and such impurity could be removed. This led to a worldwide study and production of high-purity glass fibers. When Kao first proposed that such glass fiber could be used for long-distance information transfer and could replace copper wires which were used for telecommunication during that era, his ideas were widely disbelieved; later people realized that Kao's ideas revolutionized the whole communication technology and industry.
He also played a leading role in the early stage of engineering and commercial realization of optical communication. In spring 1966, Kao traveled to the U.S. but failed to interest Bell Labs, which was a competitor of STL in communication technology at that time. He subsequently traveled to Japan and gained support. Kao visited many glass and polymer factories, discussed with various people including engineers, scientists, businessmen about the techniques and improvement of glass fiber manufacture. In 1969, Kao with M. W. Jones measured the intrinsic loss of bulk-fused silica at 4 dB/km, which is the first evidence of ultra-transparent glass. Bell Labs started considering fiber optics seriously. As of 2017, fiber optic losses (from both bulk and intrinsic sources) are as low as 0.1419 dB/km at the 1.56 µm wavelength.
Kao developed important techniques and configurations for glass fiber waveguides, and contributed to the development of different fiber types and system devices which met both civil and military[c] application requirements, and peripheral supporting systems for optical fiber communication. In mid-1970s, he did seminal work on glass fiber fatigue strength. When named the first ITT Executive Scientist, Kao launched the "Terabit Technology" program in addressing the high frequency limits of signal processing, so Kao is also known as the "father of the terabit technology concept". Kao has published more than 100 papers and was granted over 30 patents, including the water-resistant high-strength fibers (with M. S. Maklad).
At an early stage of developing optic fibers, Kao already strongly preferred single-mode for long-distance optical communication, instead of using multi-mode systems. His vision later was followed and now is applied almost exclusively. Kao was also a visionary of modern submarine communications cables and largely promoted this idea. He predicted in 1983 that world's seas would be littered with fiber optics, five years ahead of the time that such a trans-oceanic fiber-optic cable first became serviceable.
Ali Javan's introduction of a steady helium–neon laser and Kao's discovery of fiber light-loss properties now are recognized as the two essential milestones for the development of fiber-optic communications.
Kao joined the Chinese University of Hong Kong (CUHK) in 1970 to found the Department of Electronics, which later became the Department of Electronic Engineering. During this period, Kao was the reader and then the chair Professor of Electronics at CUHK; he built up both undergraduate and graduate study programs of electronics and oversaw the graduation of his first students. Under his leadership, the School of Education and other new research institutes were established. He returned to ITT Corporation in 1974 (the parent corporation of STC at that time) in the United States and worked in Roanoke, Virginia, first as Chief Scientist and later as Director of Engineering. In 1982, he became the first ITT Executive Scientist and was stationed mainly at the Advanced Technology Center in Connecticut. While there, he served as an adjunct professor and Fellow of Trumbull College at Yale University. In 1985, Kao spent one year in West Germany, at the SEL Research Center. In 1986, Kao was the Corporate Director of Research at ITT.
Kao was the vice-chancellor of the Chinese University of Hong Kong from 1987 to 1996. From 1991, Kao was an Independent Non-Executive Director and a member of the Audit Committee of the Varitronix International Limited in Hong Kong. From 1993 to 1994, he was the President of the Association of Southeast Asian Institutions of Higher Learning (ASAIHL). In 1996, Kao donated to Yale University, and the Charles Kao Fund Research Grants was established to support Yale's studies, research and creative projects in Asia. The fund currently is managed by Yale University Councils on East Asian and Southeast Asian Studies. After his retirement from CUHK in 1996, Kao spent his six-month sabbatical leave at the Imperial College London Department of Electrical and Electronic Engineering; from 1997 to 2002, he also served as visiting professor in the same department.
Kao was chairman and member of the Energy Advisory Committee (EAC) of Hong Kong for two years, and retired from the position on July 15, 2000. Kao was a Member of the Council of Advisors on Innovation and Technology of Hong Kong, appointed on April 20, 2000. In 2000, Kao co-founded the Independent Schools Foundation Academy, which is located in Cyberport, Hong Kong. He was its founding Chairman in 2000, and stepped down from the Board of the ISF in December 2008. Kao was the keynote speaker at IEEEGLOBECOM 2002 in Taipei, Taiwan. In 2003, Kao was named a Chair Professor by special appointment at the Electronics Institute of the College of Electrical Engineering and Computer Science, National Taiwan University. Kao then worked as the chairman and CEO of Transtech Services Ltd., a telecommunication consultancy in Hong Kong. He was the founder, chairman and CEO of ITX Services Limited. From 2003 to January 30, 2009, Kao was an independent non-executive director and member of the audit committee of Next Media.
Guglielmo Marconi, pioneer of wireless telecommunication, was awarded half of the 1909 Nobel Prize in Physics. In 2009, the century anniversary of Marconi's Nobel, Kao was awarded half of the same prize for his pioneer work on optical fiber which has "rewired the world". Kao was also awarded the Marconi Prize in 1985, and is a Fellow of the Marconi Society.
1978: The IEEE Morris N. Liebmann Memorial Award. Citation: "for making communication at optical frequencies practical by discovering, inventing, and developing the material, techniques and configurations for glass fiber waveguides and, in particular, for recognizing and proving by careful measurements in bulk glasses that silicon glass could provide the requisite low optical loss needed for a practical communication system".
1979: The L. M. Ericsson International Prize, Sweden
1989: The James C. McGroddy Prize for New Materials, American Physical Society (APS). Citation: "for contribution to the materials research and development that resulted in practical low loss optical fibers, one of the cornerstones of optical communications technology".
1996: The Prince Philip Medal of the Royal Academy of Engineering, UK, in recognition of "his pioneering work which led to the invention of optical fiber and for his leadership in its engineering and commercial realization; and for his distinguished contribution to higher education in Hong Kong"
November 4, 2014: Gimme Fiber Day on Kao's birthday, FTTH Councils Global Alliance
On November 4, 2021, Google celebrated Kao's birthday with a Google Doodle. The binary output in the graphic spells out 'KAO' when converted to ASCII.
Later life and death
Kao's international travels led him to opine that he belonged to the world instead of any country. An open letter published by Kao and his wife in 2010 later clarified that "Charles studied in Hong Kong for his high schooling, he has taught here, he was the Vice-Chancellor of CUHK and retired here too. So he is a Hong Kong belonger."
Pottery making was a hobby of Kao's. Kao also enjoyed reading wuxia (Chinese martial fantasy) novels.
On October 6, 2009, when Kao was awarded the Nobel Prize in Physics for his contributions to the study of the transmission of light in optical fibers and for fiber communication, he said, "I am absolutely speechless and never expected such an honor." Kao's wife Gwen told the press that the prize will primarily be used for Charles's medical expenses. In 2010 Charles and Gwen Kao founded the Charles K. Kao Foundation for Alzheimer's Disease to raise public awareness about the disease and provide support for the patients.
In 2016, Kao lost the ability to maintain his balance. At the end-stage of his dementia he was cared for by his wife and intended not to be kept alive with life support or have CPR performed on him. Kao died at Bradbury Hospice in Hong Kong on 23 September 2018 at the age of 84.
Optical fiber technology; by Charles K. Kao. IEEE Press, New York, USA; 1981.
Tackling the Millennium Bug Together: Public Conferences; by Charles K. Kao. Central Policy Unit, Hong Kong; 48 pages, 1998.
Technology Road Maps for Hong Kong: a Preliminary Study; by Charles K. Kao. Office of Industrial and Business Development, The Chinese University of Hong Kong; 126 pages, 1990.
Nonlinear Photonics: Nonlinearities in Optics, Optoelectronics and Fiber Communications; by Yili Guo, Kin S. Chiang, E. Herbert Li, and Charles K. Kao. The Chinese University Press, Hong Kong; 2002, 600 pages.
^a: Kao's major task was to investigate light-loss properties in materials of optic fibers, and determine whether they could be removed or not. Hockham's was investigating light-loss due to discontinuities and curvature of fiber. ^b: Some sources show around 1964, for example, "By 1964, a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices, the 10 or 20 dB of light loss per kilometer standard." from Cisco Press. ^c: In 1980, Kao was awarded the Gold Medal from American Armed Forces Communications and Electronics Association, "for contribution to the application of optical fiber technology to military communications". ^d: In the United States National Academy of Engineering Membership Website, Kao's country is indicated as "People's Republic of China". ^e: OFC/NFOEC – Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference
^ ab"Prof Charles K. Kao". Department of Electronic & Electrical Engineering. University College London. September 24, 2018. Archived from the original on September 14, 2010. Retrieved September 27, 2018.
^ 高錕. 香港百人 (in Cantonese, Chinese, and English). Asia Television. 2011.
^ abcdefghiKao, Charles K. (2013) [original Chinese translation published in 2005]. 潮平岸闊 – 高錕自傳 [A Time And A Tide: Charles K. Kao – A Memoir] (autobiography) (in Chinese). Translated by 許迪鏘 (First ed.). Joint Publishing (Hong Kong). ISBN978-962-04-3444-0.
^历史沿革 (in Chinese). Government of Jinshan District, Shanghai. Archived from the original on September 28, 2018. Retrieved September 27, 2018.
^國務院關於行政區劃變更的決定(PDF). 國務院公報 (in Chinese). 1958 (34): 717. December 6, 1958. Archived(PDF) from the original on December 1, 2020. Retrieved March 11, 2019.
^ abcFan, Yanping (范彦萍) (October 10, 2009). 诺贝尔得主高锟的堂哥回忆:他兒时国学功底很好 [Interview of Kao's cousin]. Youth Daily (in Chinese). Shanghai. Archived from the original on October 11, 2009. Retrieved October 9, 2009 – via eastday.com.
^高錕. 傑出華人系列 (documentary and oral history) (in Cantonese, Chinese, and English). Radio Television Hong Kong. 2000. Event occurs at 12:00 to 13:00. Retrieved September 27, 2018.
^陶家骏 (June 1, 2008). 著名女教育家陶玄 [Famous Female Educator Tao Xuan]. 绍兴县报 [Shaoxing County News] (in Chinese). Archived from the original on March 13, 2012. Retrieved October 9, 2009.
^「光纖之父」高錕離世 享年84歲 (16:56). Online instant news section. Ming Pao (in Chinese). Hong Kong: Media Chinese International. September 23, 2018. Archived from the original on September 23, 2018. Retrieved September 27, 2018.
^高锟个人简历 [The biography of Charles K. Kao] (in Chinese). chinanews.com.cn. October 6, 2009. Archived from the original on October 8, 2009. Retrieved October 9, 2009.
^ ab光纤与爱情——高锟一生的实验. Ming Pao. Hong Kong. March 4, 2000. Archived from the original on February 21, 2009. Retrieved October 7, 2009 – via networkchinese.com.
^ ab高錕履歷 [resume of Kao Kuen]. Wen Wei Po (in Chinese). Hong Kong. 7 October 2009. Archived from the original on September 28, 2018. Retrieved 27 September 2018.
^高錕. 傑出華人系列 (documentary and oral history) (in Cantonese, Chinese, and English). Radio Television Hong Kong. 2000. Event occurs at around 20:00. Retrieved September 27, 2018.
^"Draper Prize". draper.comg. Archived from the original on February 14, 2010. Retrieved November 4, 2009. "Charles Kao is credited for first publicly proposing the possibility of practical telecommunications using fibers in the 1960s."
^Montgomery, Jeff D. (March 22, 2002). "Chapter 1 – History of Fiber Optics". In DeCusatis, Casimer (ed.). Fiber optic data communication: technological trends and advances (1st ed.). Academic Press. 1.3.1. Long Road to Low-Loss Fiber (pp. 9–16). ISBN978-0-12-207891-0.
^1999 Charles Stark Draper Award PresentedArchived May 5, 2010, at the Wayback Machine "Kao, who was working at ITT's Standard Telecommunications Laboratories in the 1960s, theorized about how to use light for communication instead of bulky copper wire and was the first to publicly propose the possibility of a practical application for fiber-optic telecommunication."
^Technology of Our Times: People and Innovation in Optics and Optoelectronics (SPIE Press Monograph Vol. PM04), by Frederick Su; SPIE Publications (July 1, 1990); ISBN0-8194-0472-1, ISBN978-0-8194-0472-5. Page 82–86, Terabit Technology, by Charles K. Kao.
^香港两座建筑物将以高锟及饶宗颐名字命名(图) [Two landmark buildings in Hong Kong are named after Charles K. Kao and Rao Zongyi (with photos)] (shtml) (in Chinese). Ifeng News. December 30, 2009. Archived from the original on October 6, 2010. Retrieved January 3, 2009.
^高錕. 傑出華人系列 (documentary and oral history) (in Cantonese, Chinese, and English). Radio Television Hong Kong. 2000. Event occurs at around 38:00. Retrieved September 27, 2018. 我對每一個國家，每一個種族感情都差不多。。。。。。我是以人為主，不是以國家或種族為主。。。。。。我變成了世界中間的一部份，不是任何國家的一部份。
高錕. 傑出華人系列 (documentary and oral history) (in Cantonese, Chinese, and English). Radio Television Hong Kong. 2000. Retrieved September 27, 2018.
"Oral-History:Charles Kao". Engineering and Technology History Wiki (oral history transcript). Interview Conducted by Robert Colburn. September 26, 2018 [interview conducted in 2004]. Retrieved September 27, 2018.CS1 maint: others (link)
Kao, Charles K. (2010). A Time and A Tide: Charles K. Kao ─ A Memoir (autobiography). Chinese University Press. ISBN9789629969721.
Kao, Charles K. (2013) [the translation first published in 2005]. 潮平岸闊——高錕自傳 [A Time And A Tide: Charles K. Kao ─ A Memoir] (autobiography) (in Chinese). Translated by 許迪鏘 (First ed.). Joint Publishing (Hong Kong). ISBN978-962-04-3444-0.