Charles K. Kao and the Nobel Prize: How CUHK Commemorates the "Father of Fibre Optics

# Charles K. Kao and the Nobel Prize: How CUHK Commemorates the "Father of Fibre Optics"

In one sentence: Charles K. Kao (1933–2018), the "Father of Fibre Optics", was awarded half of the 2009 Nobel Prize in Physics alone. CUHK commemorates this with a permanent exhibition of the Nobel medal at the University Gallery, the Charles Kuen Kao Building, and a bronze statue, while the adjacent Hong Kong Science Park honours him with the 288-seat "Golden Egg" Charles K. Kao Auditorium (opened 2007).

Formatting note: The complete biography of Charles Kuen Kao at CUHK—his founding of the Department of Electronics in 1970, his tenure as the third Vice-Chancellor (1987–1996), and the commemorative systems of statues and scholarships—is detailed in charles-kao-vice-chancellor.md. The "affiliation strength" classification of scholars with Nobel, Fields, or Turing prizes connected to CUHK is catalogued in nobel-and-awards.md. This article does not repeat his administrative narrative; it focuses on three things: the scientific threshold of that 2009 half-Nobel, the geographical attribution of the commemorative facilities (especially the "Golden Egg", often mistakenly thought to be on CUHK campus), and the continuation of the fibre optics legacy on campus and at Pak Shek Kok.

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A Nobel Prize awarded for "that beam of light in glass," a conference centre nicknamed the "Golden Egg" that sits outside the university campus, and a commemorative exhibition opening at the foot of the hill in 2025, running until the end of 2026—the marks Charles K. Kao left on this patch of land are scattered within and beyond the campus, their attribution frequently muddled. The core of his 1966 paper was, at heart, a judgement so simple it almost seemed to defy common sense: glass couldn't carry light far not because of light scattering, but simply because the glass wasn't pure enough. Forty-three years later, the Royal Swedish Academy of Sciences awarded half of the physics prize to that judgement. This article clarifies the full story behind that half-Nobel and the different ways CUHK and the adjacent Science Park have chosen to commemorate him.

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# Why did Charles Kao receive half of the 2009 Nobel Prize in Physics alone?

The 2009 Nobel Prize in Physics was divided into two halves. According to the official Nobel Prize facts^※, one half was awarded to Charles K. Kao for "groundbreaking achievements concerning the transmission of light in fibres for optical communication." The other half was shared by American scientists Willard S. Boyle and George E. Smith for the invention of the charge-coupled device (CCD, the digital imaging sensor). This means Kao did not "share" the same half with the other two; he solely claimed one entire half of the prize—a distinction that later determined the weight of CUHK's claim to a Nobel laureate.

Kao's half-prize traces its roots to a single paper in 1966. According to the English Wikipedia^※, he co-authored "Dielectric-Fibre Surface Waveguides for Optical Frequencies" with British engineer George Hockham, published in the Proceedings of the Institution of Electrical Engineers. At the time, the prevailing industry view was that glass fibres could transmit light for only a few metres before the signal attenuated to nothing and could never be used for long-distance communication. Kao's paper dismantled this "impossibility" by demonstrating that the chief cause of signal loss was not intrinsic physical effects like light scattering within the glass, but rather the absorption of light by impurities in the glass (primarily transition metal ions such as iron). If the glass could be purified sufficiently, loss could be pushed below the practical threshold.

This "practical threshold" was a specific number: reducing attenuation below 20 decibels per kilometre (20 dB/km). According to the Hong Kong Laureate Forum profile^※, Kao deduced from this that optical fibres made of highly purified silica glass could carry light signals for several kilometres without being completely annihilated—a target in 1966 that bordered on delusion (the best glass at the time had an attenuation of roughly 1000 dB/km). Four years later, in the 1970s, the laboratories of Corning Glass Works in the United States were the first to produce a low-loss optical fibre that met the target, confirming Kao's judgement. By 1981, according to the same source, the first commercial fibre-optic communication system was operational. From a paper assertion to the global backbone network, fibre optics took about fifteen years.

The key facts of this half-Nobel are summarised below:

An often-overlooked detail: Kao did not patent the core concept of optical fibre. Instead, he published the research openly, leaving it for laboratories and manufacturers worldwide to follow up. According to the English Wikipedia, this decision not to erect barriers is regarded by posterity as one of the accelerators that allowed fibre optics to blanket the world within just over a decade—it turned a potentially monopolised technology into the common foundation of the internet age.

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# How exactly does optical fibre transmit light, and which bottleneck did Kao solve?

To grasp the significance of Kao's half-Nobel, one must first understand how optical fibres guide light, and exactly which link he conquered. An optical fibre is an extremely thin strand of glass, structurally composed of two layers: a "core" and a surrounding "cladding," whose refractive indices differ slightly. When light enters the core at a suitable angle, it undergoes continuous total internal reflection at the interface between the core and cladding, becoming "trapped" within the core and propagating forward, bouncing as if in a mirrored tunnel, without leaking out of the glass strand. This is the geometric prerequisite for an optical fibre to "guide" light. This optical principle was well known long before Kao and was not his invention.

What Kao truly conquered was not "can light be trapped inside glass?" but "how far can light travel while trapped?". According to the English Wikipedia's^※ account of the 1966 argument, even if glass fibres could guide light that year, the signal would attenuate drastically over extremely short distances, ruling them out for communication. The academic consensus at the time largely attributed this attenuation to "intrinsic" losses like light scattering within the glass. If that were true, then loss would be the physical destiny of glass as a material, impossible to improve. Kao's critical contribution was to re-attribute the source of the loss: he argued that the attenuation primarily came from removable impurities in the glass (especially the absorption of light by transition metal ions), not from insurmountable scattering. Once this re-attribution held, the conclusion that "fibre optics is impossible for long-distance transmission" was downgraded from "physics forbids it" to "the manufacturing process isn't there yet"—and the problem suddenly had a solution.

This step of "re-attribution" is Nobel-calibre precisely because it revived a research direction that had been sentenced to death. It offered not merely a pessimistic or optimistic judgement, but an actionable engineering route: purify the glass to push attenuation below 20 dB/km. According to the Hong Kong Laureate Forum^※, it was along this route that materials scientists laboured for years, tackling the preparation of ultra-high-purity silica glass, eventually producing viable fibre in the 1970s. One could say Kao's paper did not personally fabricate a single usable optical fibre, but it pinpointed exactly "which direction to push"—and in the history of science, pointing in the right direction is often rarer than taking the first step.

An analogy helpful for a lay audience: total internal reflection solves "how to make light turn corners without escaping" (the geometry of the fibre)—this was understood before Kao. Kao solved "how to make light travel far without dying out" (the purity of the glass)—this was his 1966 breakthrough. The former determines whether fibre can be used; the latter determines whether fibre can be used over long distances. And the value of communication lies entirely in those words "long distances." The Nobel Prize was awarded for the latter half.

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# Is the label "first Nobel laureate of Hong Kong origin" accurate?

Charles Kao is often called the "first Nobel laureate of Hong Kong origin." According to the Hong Kong Science Park's introduction to Kao^※, after winning the prize in 2009, he became known as "the first Nobel laureate to hail from Hong Kong." Two qualifiers are needed for this description to be precise. First, Kao was born in Shanghai in 1933 and only came to Hong Kong for secondary school as a teenager; "Hong Kong origin" refers to the place where he grew up and built his career, not his birthplace. Second, he had previously acquired British citizenship and later American citizenship, his identity spanning China, the UK, and the US—the affiliations listed in the Nobel Prize official materials reflect precisely this cross-territory career arc.

For CUHK, the label "Hong Kong origin" matters less than the institutional affiliation listed on the award. According to the English Wikipedia^※, when the 2009 Nobel Prize announced Kao's affiliated institutions, it listed both the Standard Telecommunication Laboratories in the UK (where the 1966 paper was completed) and The Chinese University of Hong Kong—this marked the first time a Hong Kong research institution had appeared on the affiliation list of a Nobel laureate. Kao completed his foundational work in 1966 while at a British laboratory, but his subsequent twenty-six years of academic belonging (returning to Hong Kong in 1970 to found a department, serving as Vice-Chancellor from 1987 to 1996, and later as Honorary Professor of Engineering) were all at CUHK. The Nobel committee therefore listed both places side by side.

This also explains why, within the genealogy of "Nobel laureates associated with CUHK," Kao is the only one whose affiliation can be described as "achievement listed under CUHK." Figures like Yang Chen-ning, Sir James Mirrlees, and Robert Mundell taught at CUHK long-term as Professors-at-Large, but their prize-winning work was not done at CUHK; their relationship with the university is one of "long-term distinguished appointment" rather than "achievement affiliation." The strict classification of these association strengths is detailed in nobel-and-awards.md. This article only emphasises one point: Kao's half-Nobel represents the strongest possible association with CUHK—Vice-Chancellor + department founder + institutional affiliation listed—a triple overlay, not the reflected glory of a single visiting lecture.

According to the Hong Kong Laureate Forum^※, Kao was diagnosed with Alzheimer's disease in 2004, and his speech function gradually declined. As a result, his Nobel Lecture in Stockholm in December 2009 was delivered on his behalf by his wife, Mrs. Gwen Kao. The title of the lecture was "Sand from centuries past; Send future voices fast"—the "sand" in the title refers directly to silica sand, the raw material of glass. This titular phrase has since become a repeated motif in commemorations of Kao everywhere, and is also the origin of the name for the "Sparks from the Sand" exhibition at the Science Park, discussed later.

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# Where is the Charles K. Kao Auditorium? Why is it not on the CUHK campus?

This is the point most easily confused: when one mentions the "Charles K. Kao Auditorium," quite a few people assume it is situated on the CUHK campus. This is not the case. According to the Hong Kong Science Park entry (Wikipedia)^※, the Charles K. Kao Auditorium is located in the Hong Kong Science Park. It is a lecture hall with 288 seats, completed in early 2007 as part of Science Park Phase 2. Known for its distinctive spherical shape, it is popularly called the "Golden Egg" and serves as the architectural landmark of the entire Science Park. The Science Park is situated on the shore of Tolo Harbour at Pak Shek Kok, Sha Tin District, New Territories—separated from the CUHK campus by only a strip of water and within walking distance, yet it is an independent legal entity operated by the Hong Kong Science and Technology Parks Corporation (HKSTP), a separate organisation from CUHK.

The auditorium was named after Kao because of his personal connection to the Science Park itself. According to the Hong Kong Science Park materials^※, Kao served as a member of the Board of Directors (former director) of the Hong Kong Science Park company and was one of the main advocates pushing for the establishment of a science park in Hong Kong. One point needs clarification: there is an occasional rumour that "Kao served as the Science Park's first CEO," but publicly available records only support his status as a "director," with no reliable record of him being the "first CEO," so this article records him in the capacity of director. According to the Science Park's introduction to the auditorium^※, naming this landmark after Kao was done "in honour of his visionary achievements that have revolutionised modern communication."

Thus, a cross-institutional, cross-perimeter commemorative geography has formed around this Nobel laureate Vice-Chancellor. The same individual is memorialised by the "Charles Kuen Kao Building" and a bronze statue inside the CUHK campus, and by the "Golden Egg" Charles K. Kao Auditorium just over the wall in the Science Park. The two sites are separated by barely more than a kilometre, yet belong to two different systems: the university and the Science Park. Juxtaposing them illuminates the duality of Kao's identity—he was simultaneously a university Vice-Chancellor (CUHK's institutional memory) and an industry catalyst (the founding advocate of the Science Park). The table below clarifies the attribution of these two sets of memorial facilities that are often conflated:

A boundary that needs clarifying: this article's clarification that the "Golden Egg" is not on the CUHK campus is not an attempt to excise it from Kao's commemorative map, but to establish that it was named and is operated by the Science Park, not CUHK. For a figure who simultaneously nurtured a research university and a technology park at Pak Shek Kok, the scattering of his memorials across two institutions, on two sides of a fence, is itself testimony to the spillover of his influence. The Charles Kuen Kao Building, the bronze statue, and the scholarship system on the CUHK campus (whose establishment and donation details are found in charles-kao-vice-chancellor.md), together with the Science Park's "Golden Egg," collectively form a commemorative inventory of "one man straddling two systems."

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# On the CUHK campus, what are the Nobel marks commemorating Charles Kao?

Inside the CUHK campus, the core imprint directly linked to the "Nobel Prize" is the set of medals housed in the University Gallery. According to the University Gallery Zone D "Pathfinders" materials^※, the gallery features a permanent exhibition of numerous major honours Kao donated to CUHK. These include the 1977 Stuart Ballantine Medal from the Franklin Institute (USA), the 1979 L.M. Ericsson International Prize, the 1985 IEEE Alexander Graham Bell Medal, the 1996 Prince Philip Medal from the Royal Academy of Engineering (UK), the 1999 Charles Stark Draper Prize from the US National Academy of Engineering, and, most notably, the 2009 Nobel Prize in Physics medal and diploma. This collection of medals was permanently donated to CUHK by Kao in 2010 and is now displayed in glass cases for public viewing—it is the only place on campus where one can see the actual Nobel medal with one's own eyes.

The Nobel items first made their public debut in a special exhibition in early 2010. According to university exhibition materials and contemporary reports, Kao's first public appearance back in Hong Kong after receiving the Nobel Prize was at CUHK. The university promptly mounted an exhibition titled "The Lore of a Laureate," showcasing his Nobel medal and diploma for the first time. Accounts from the University Gallery note that the exhibition, originally scheduled to close in early spring, was so well received that it was extended until the autumn of the same year, drawing tens of thousands of visitors—a level of enthusiasm reflecting the symbolic weight the Nobel medal carries for the campus community. Subsequently, these items transitioned from a temporary special exhibition to a permanent fixture in the University Gallery, completing the shift from "one-off appearance to long-term collection."

As for the two other memorials on campus that students and staff pass more routinely—the Charles Kuen Kao Building (the Science Centre North Block, named in 1996) and the bronze statue unveiled outside the Ho Sin-Hang Engineering Building in September 2010—the complete background of their naming, unveiling, sculptor, and specifications is detailed in charles-kao-vice-chancellor.md and will not be elaborated here. What needs to be pointed out in the context of "Nobel commemoration" is their functional division of labour. The Charles Kuen Kao Building is a form of daily, year-round visible physical commemoration (a building where classes are held every day). The bronze statue is a form of ritualised, person-focused commemoration (a figure at which one pauses). And the Nobel medal in the University Gallery is curated, viewable-up-close material proof (the actual medal locked in a display case). They operate on three different levels, together forming the commemorative trio within the CUHK campus.

The process by which this Nobel medal transformed from a "private honour" into a "public collection" is itself worth noting. Kao could easily have kept the Nobel medal as a private possession, or donated it to any of the places where he grew up or worked. He ultimately chose, along with seventeen other major awards, to entrust it to CUHK, placing the entire half-century sequence of his personal honours in the care of this university. For the university, the significance of these physical objects goes beyond being "exhibits"—they offer tangible proof of the abstract institutional statement that "CUHK is listed on a Nobel Prize," something you can see through glass, and can point out to students. A real medal locked in a display case tells successive cohorts of new students, far more effectively than any text, that this university's connection to that half-Nobel is a substantive link, not name-dropping.

An inherent tension within the campus commemoration is worth recording: Kao's foundational work in 1966 was completed in the UK, and when he won the prize in 2009, he had already stepped down as Vice-Chancellor for over a decade. Yet the university can still justifiably display this Nobel medal—on the basis of "institutional affiliation." Since the Nobel committee wrote CUHK into Kao's listed affiliations, the university gained the legitimacy to incorporate this medal into its history. The University Gallery's display of it alongside the seventeen other awards presents not "a solitary Nobel," but an engineer's complete sequence of lifelong honours, of which the Nobel is simply the brightest piece.

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# "Sparks from the Sand": what does the Science Park's new 2025–2026 memorial exhibition say?

Seven years after Kao's passing in 2018, the Science Park, adjacent to CUHK, has mounted a new exhibition for him. According to the official Hong Kong Science Park events page^※, a memorial exhibition titled "Sir Charles K. Kao's Story: Sparks from the Sand" opened on 10 September 2025 on the ground floor of Building 10W at the Hong Kong Science Park, with a run extending to 31 December 2026—a long-term exhibition lasting over a year, not a brief anniversary event. The theme closely echoes the imagery of Kao "creating fibre from sand," in keeping with the "sand" of his Nobel Lecture title.

According to the same events page, the exhibition's intent is not merely retrospective but also inspirational: the official wording states the hope that the exhibition will "inspire more innovators to embrace Sir Kao's pioneering spirit to pursue ground-breaking discoveries towards success." In other words, the Science Park has cast its Kao memorial exhibition as a piece of "spiritual teaching material" aimed at the park's innovation and technology community. For an institution whose mission is to incubate tech start-ups, this orientation of "using past sages to motivate successors" forms a subtle contrast with the University Gallery's more "historical archival" focus.

Viewed within the context of the "Golden Egg," this exhibition adds a dynamic layer to the Science Park's commemoration of Kao. Previously, the Science Park's memorial primarily consisted of the static naming of the "Golden Egg" Charles K. Kao Auditorium—an architectural landmark bearing his name. The "Sparks from the Sand" exhibition, beginning in 2025, represents an active effort in content curation, retelling Kao's story for a new generation of entrepreneurs within the park. Naming carves a name onto a building; curating tells a spirit to living people. With these two combined, the Science Park's commemoration of Kao expands from "a building" into "a story still being told."

A distinction necessary for clarity: "Sparks from the Sand" is organised by the Hong Kong Science and Technology Parks Corporation, and its venue is the Science Park, not the CUHK campus. It is independent from and runs parallel to the permanent Nobel medal exhibition at the CUHK University Gallery. For visitors, this means that if one intends to "see Kao," there are actually two distinct routes in the Pak Shek Kok area—entering CUHK campus to see the University Gallery's real medal and the bronze statue, or going just over the wall to the Science Park to see the "Golden Egg" and the "Sparks from the Sand" exhibition. These two routes are a stone's throw apart, yet belong to two different institutions.

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# How does the Nobel Prize of the Father of Fibre Optics still resonate at CUHK and Pak Shek Kok?

When Charles Kao arrived at CUHK in 1970 to establish the Department of Electronics, fibre-optic communication was still a paper assertion in the lab. By the time of his passing in 2018, the optical fibres underpinning the global internet had been laid across continents and oceans. This trajectory, "from a single paper to world infrastructure," has left two kinds of continuation on the land at Pak Shek Kok: one in the research agenda, and one in the innovation and technology ecosystem.

On the research side, Kao's core concept of "using light to carry information" remains an active frontier in CUHK's engineering disciplines to this day, rather than a historical exhibit. According to public records from the CUHK Research Portal^※, the Faculty of Engineering at CUHK continues to produce results in photonics and fibre-optic-related directions, covering applied topics such as precision fibre-optic alignment and packaging, and tunable optical delay lines. In the current era of exploding data and AI data centres thirsting for transmission bandwidth, making light travel faster and more efficiently through both optical fibres and photonic chips remains the main battlefield for global optical communication research. Kao's original approach of pushing attenuation below 20 dB/km—starting from materials and structure to approach the physical limit—remains the methodological bedrock of this field.

On the ecosystem side, one must return to the "Golden Egg." The Hong Kong Science Park, which Kao fervently advocated, is now the core carrier of Hong Kong's innovation and technology drive, and the Charles K. Kao Auditorium named after him serves as one of the park's most frequently used stages for technology forums, product launches, and academic events. According to the Hong Kong Science Park events page^※, the park casts Kao as a symbol of "pioneering spirit," encouraging entrepreneurs to follow his example. Thus, Charles Kao's name has two distinct "usages" at Pak Shek Kok. At CUHK, it is a teaching building, a bronze statue, a Nobel medal in a glass case—pointing to completed achievements. At the Science Park, it is a lecture hall used for meetings every day and an exhibition inspiring entrepreneurs—pointing to a future still unfolding. These two usages do not conflict; they are complementary. The university is responsible for properly curating a sage's accomplishments for posterity to admire, while the park is responsible for translating that same sage's spirit into a summons for those who come after. Perhaps the best way to commemorate someone is, by nature, meant to include both layers—"remembering what he did" and "urging others to carry on." Kao's commemoration on the two sides of the water at Pak Shek Kok assigns these two layers, precisely, to the university and the park respectively.

According to the Hong Kong Laureate Forum^※, Kao once described his own motto: "After my passing away, I would have left a mark on the world, like footprints in the sand." Reading this alongside the title of his Nobel Lecture reveals a resonant closed loop: his life's work was to purify the humblest sand (silica sand, the raw material of glass) into optical fibres that could carry the human voice; and the aspiration he set for himself was to leave footprints in that very sand. Sand was both his raw material and his epitaph metaphor.

In this sense, the answer to the question "How does CUHK commemorate Charles Kao?" actually extends beyond the walls of a single university. The Nobel medal is locked in the CUHK University Gallery, the "Golden Egg" stands just outside the walls in the Science Park, but his truest, most expansive, and most invisible monument is every single optical fibre currently carrying light—an invisible memorial woven across the globe, impossible to count in full. According to a memorial article by CUHK Communications and Public Relations^※, the university's tribute encapsulated his bond with CUHK with the word "home"—he attended secondary school in Hong Kong, served as Vice-Chancellor at CUHK, and retired in Hong Kong; this land was both the starting point of his career and his ultimate destination.

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# See also

• Charles Kao and CUHK: A Comprehensive Archive – From Founding the Department of Electronics to Nobel Laureate Vice-Chancellor (1970–2018) — A full archive on Kao's department founding, university governance, statue, and scholarship system.
• Top Scholars Associated with CUHK (Nobel/Fields/Turing) — The classification of association strength between "achievement listed under CUHK" and "Professor-at-Large."
• Notable Professors, Academic Leaders, and Biographies at CUHK — Portraits of successive Vice-Chancellors and masters across various disciplines.

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