Charles Kao and the Fibre-Optic Nobel: How CUHK Remembers Its "Father of Fibre Optics" President

The short answer: Charles Kao (1933–2018), the "father of fibre optics," alone received half of the 2009 Nobel Prize in Physics. CUHK honours him with a permanent display of his Nobel medal in the University Gallery, the Charles Kuen Kao Building, and a bronze statue; next door, Hong Kong Science Park named its 288-seat "Golden Egg" auditorium the Charles K. Kao Auditorium in 2007.

A note on scope: Charles Kuen Kao's full CUHK biography — founding the Department of Electronics in 1970, serving as the University's third Vice-Chancellor from 1987 to 1996, the bronze statue and scholarship system — is covered in charles-kao-vice-chancellor.md. The "strength of affiliation" grading for Nobel/Fields/Turing laureates linked to CUHK is in nobel-and-awards.md. This piece does not revisit his administrative legacy. It focuses on three things only: the scientific threshold behind that half-Nobel of 2009, the geographical ownership of the memorials (especially the "Golden Egg," which people often mistake for being on campus), and how the fibre-optic legacy continues across campus and Pak Shek Kok.

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A Nobel prize for "the light inside a piece of glass," a conference centre nicknamed the "Golden Egg" that isn't on the university campus at all, and a memorial exhibition that opened at the foot of the hills in 2025 and runs until the end of 2026 — the marks Charles Kao left on this stretch of land are scattered inside and outside the campus, and people routinely mix up which is which. The core of his 1966 paper was, in fact, a judgement so plain it almost offends common sense: glass fails to carry light far, not because of scattering, but simply because the glass is not pure enough. Forty-three years later, the Royal Swedish Academy of Sciences awarded half the Physics Prize to that judgement. This piece sets out the full story behind that half-Nobel — and how CUHK and the neighbouring science park each choose to remember him.

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

The 2009 Nobel Prize in Physics was awarded in two halves. According to the official Nobel Prize citation^※, one half went to Charles Kao "for groundbreaking achievements concerning the transmission of light in fibres for optical communication"; the other half was shared between American scientists Willard S. Boyle and George E. Smith for inventing the charge-coupled device (CCD — the light-sensing element behind digital imaging). In other words, Kao did not "share" his half with the other two. He alone received one half of the entire prize — a distinction that determines the weight of CUHK's claim to a Nobel laureate.

The root of Kao's half-prize lies in a 1966 paper. According to English Wikipedia^※, he co-authored "Dielectric-Fibre Surface Waveguides for Optical Frequencies" with British engineer George Hockham, published in the journal of the Institution of Electrical Engineers. At the time, the prevailing view in the industry was that light travelling through glass fibre faded out after a few metres; long-distance communication was simply out of the question. Kao's paper took that "impossibility" apart, arguing that the dominant cause of signal loss was not physical effects such as scattering of light within the glass, but impurities in the glass itself — chiefly metal ions such as iron that absorb light. Purify the glass well enough, he argued, and losses could be brought below the threshold of practical use.

That "practical threshold" has a specific number: attenuation of no more than 20 decibels per kilometre (20 dB/km). According to the Hong Kong Laureate Forum profile^※, Kao calculated that optical fibre made from high-purity silica glass could carry light signals for several kilometres without complete annihilation — a goal that in 1966 bordered on "talking through one's hat" (the best glass of the day attenuated light by roughly 1,000 dB/km). Four years into the next decade, in the 1970s, researchers at the American company Corning produced the first low-loss fibre that met the target, vindicating Kao's judgement. By 1981, according to the same source, the first commercial fibre-optic communication system was built and put into service. From a paper's assertion to the global backbone network, fibre optics took about fifteen years.

Here are the key facts of that half-Nobel at a glance:

A detail often overlooked: Kao never filed a patent for the core idea of fibre optics. Instead, he published his findings openly, leaving laboratories and manufacturers around the world free to follow up. According to English Wikipedia, this choice to build no moats around the idea is regarded as one of the accelerators that allowed fibre to spread across the globe in little over a decade — turning what could have been a monopolised technology into the public foundation of the internet age.

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# How does fibre actually transmit light? Which bottleneck did Kao crack?

To grasp the weight of Kao's half-Nobel, you first need to understand how optical fibre carries light — and which link in the chain he actually solved. An optical fibre is an extremely thin glass thread with two layers: the core at the centre and the surrounding cladding, made of glass with a slightly different refractive index. When light enters the core at the right angle, it undergoes total internal reflection repeatedly at the boundary between core and cladding — bouncing along as if trapped in a mirrored tunnel, unable to escape the thread. That is the geometric precondition that lets a fibre "guide" light. This principle of optics was well understood long before Kao; it was not his invention.

What Kao actually cracked was not "can light be trapped inside glass," but "how far can trapped light travel." According to English Wikipedia^※'s account of the 1966 thesis, even when glass fibre could guide light, the signal decayed catastrophically over very short distances, and the material was therefore judged useless for communication. At the time, most researchers attributed the loss to "intrinsic" effects such as scattering inside the glass — if that were true, the attenuation would be a physical destiny of glass as a material, with no room for improvement. Kao's crucial contribution was to re-attribute the source of the loss: he argued that attenuation came chiefly from removable impurities in the glass (above all, the absorption of light by transition-metal ions), not from insurmountable scattering. Once that re-attribution stood, the verdict "optical fibre cannot carry light far" was downgraded from "physics forbids it" to "our manufacturing is not good enough" — and the problem suddenly had a solution.

That step of "re-attribution" is Nobel-grade precisely because it rescued a line of research that had been sentenced to death. It offered not just a pessimistic or optimistic judgement, but a workable engineering route: purify the glass and push attenuation below 20 dB per kilometre. According to the Hong Kong Laureate Forum^※, it was along this route that materials scientists spent years perfecting the preparation of ultra-high-purity silica glass, finally producing fibre that met the target in the 1970s. Kao's paper never built a working fibre with its own hands — but it pointed precisely at "where the effort should go." In the history of science, pointing in the right direction is often scarcer than taking the first step.

An analogy for the lay reader: total internal reflection answers "how to make light turn corners without escaping" (the geometry of the fibre) — that was known before Kao. Kao answered "how to make light travel far without dying out" (the purity of the glass) — that was his breakthrough of 1966. The former decides whether fibre can be used at all; the latter decides whether it can be used over long distances — and the entire value of communication lies precisely in those two words, "long distances." It was the latter half that the Nobel recognised.

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# Is "first Nobel laureate from Hong Kong" accurate?

Kao is often called the "first Nobel laureate from Hong Kong." According to Hong Kong Science Park's introduction to Kao^※, after winning in 2009 he became "the first Nobel laureate to hail from Hong Kong." That phrasing needs two qualifications before it is accurate. First, Kao was born in Shanghai in 1933 and only came to Hong Kong for secondary school; "from Hong Kong" refers to where he grew up and built his career, not his birthplace. Second, he had already taken British nationality and later American nationality, so his identity spanned China, Britain and America — a cross-border trajectory reflected in the institutional affiliations listed in the official Nobel records.

For CUHK, what truly carries weight is not the "from Hong Kong" label but the institutional listing. According to English Wikipedia^※, when the 2009 Nobel announcement listed Kao's affiliations, it named both Britain's Standard Telecommunication Laboratories (where the 1966 paper was completed) and The Chinese University of Hong Kong — the first time a Hong Kong research institution had ever appeared in a Nobel laureate's list of affiliations. Kao was at the British laboratory when he did the foundational work in 1966, but his academic home for the following twenty-six years — returning to Hong Kong in 1970 to found the department, serving as Vice-Chancellor from 1987 to 1996, then holding a chair professorship of engineering — was CUHK. Hence the Nobel committee's dual listing.

This also explains why, in the genealogy of "Nobel scholars affiliated with CUHK," Kao is the only one whose achievement can be said to carry the University's name. Yang Chen-Ning, Sir James Mirrlees and Robert Mundell all taught at CUHK for long stretches as Distinguished Professor-at-Large, but the work for which they won their prizes was not done at CUHK; their relationship to the University was one of "long-term appointment" rather than "achievement listed under the institution." The strict grading of these affiliations is set out in nobel-and-awards.md. This piece makes one point only: for CUHK, Kao's half-prize is the strongest possible affiliation — Vice-Chancellor + department founder + institutional listing layered on top of each other — not the reflected glory of a one-off guest lecture.

According to the Hong Kong Laureate Forum^※, Kao was diagnosed with Alzheimer's disease in 2004, and his speech gradually declined. At the Nobel lecture in Stockholm in December 2009, his wife, Mrs. Gwen Wong Kao, read his address on his behalf, titled "Sand from centuries past; send future voices fast." The "sand" in that title is precisely silica sand, the raw material of glass. The phrase has since become an image repeatedly invoked wherever Kao is commemorated — and it is the origin of the name of the science park's "Sparks from the Sand" exhibition discussed below.

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# Where is the Kao Auditorium, and why is it not on the CUHK campus?

This is the most commonly confused point: mention "the Charles K. Kao Auditorium" and many assume it sits on the CUHK campus. It does not. According to Hong Kong Science Park materials (Wikipedia)^※, the Charles K. Kao Auditorium is located in Hong Kong Science Park: a lecture hall with 288 seats, completed in early 2007 along with Phase 2 of the park. It is known for its distinctive spherical form, nicknamed the "Golden Egg," and serves as the architectural landmark of the whole park. The park sits on the Pak Shek Kok waterfront in Sha Tin, New Territories, along Tolo Harbour — within walking distance of and separated by water from the CUHK campus — but it is an independent corporate entity operated by the Hong Kong Science and Technology Parks Corporation (HKSTP). Two organisations, not one.

The auditorium is named after Kao because of his own ties to the park. According to Hong Kong Science Park materials^※, Kao served as a member of the board of directors of the Hong Kong Science Park Corporation and was one of the principal advocates for establishing the park in Hong Kong. A clarification is in order: the occasional claim that Kao was the park's "first chief executive" is not supported by any reliable public record — only his directorship is documented — so this piece follows the directorship version. According to the Science Park's introduction to the auditorium^※, the landmark was named for Kao "in honour of his visionary achievements that have revolutionised modern communication."

A commemorative geography has thus grown up around this Nobel-president that is cross-institutional and cross-boundary: the same man has a "Kao Building" and a bronze statue on the CUHK campus, and a "Golden Egg" auditorium in the science park just beyond the wall. The two sites are barely a kilometre apart, yet they belong to two separate systems — the university and the technology park. Setting them side by side reveals the duality of Kao's identity: he was both a university vice-chancellor (part of CUHK's institutional memory) and an industry champion (the initiator of the science park). The table below untangles the two sets of memorials that are constantly mixed up:

The boundary should be stated plainly: this piece points out that the "Golden Egg" is not on the CUHK campus not to strike it from Kao's commemorative map, but to make clear that it was named and is operated by the science park, not the University. For a man who, at Pak Shek Kok, nurtured both a research university and a technology park in the same stretch of land, having memorials scattered across two institutions and two sides of a wall is itself evidence of how far his influence spilled over. The Kao Building, the statue and the scholarship system on campus (whose establishment and donation details are in charles-kao-vice-chancellor.md), together with the science park's "Golden Egg," form a commemorative dossier spanning two systems for one man.

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# On the CUHK campus, what Nobel-related memorials are there?

The core Nobel-related memorial on the CUHK campus is the collection of medals in the University Gallery. According to University Gallery Zone D "開新探微" materials^※, the Gallery's permanent collection includes a number of major honours Kao donated to CUHK: the 1977 Stuart Ballantine Medal of the Franklin Institute (USA), the 1979 L.M. Ericsson International Prize, the 1985 IEEE Alexander Graham Bell Medal, the 1996 Prince Philip Medal of the Royal Academy of Engineering (UK), the 1999 Charles Stark Draper Prize of the US National Academy of Engineering — and, most prominently, the 2009 Nobel Prize in Physics medal and diploma. Kao donated this body of medals to CUHK permanently in 2010; it now sits in glass display cases for the public, the only place on campus where you can see the actual Nobel medal with your own eyes.

The medals' first public appearance was a themed exhibition in early 2010. According to the University's exhibition materials and contemporary reporting, Kao's first public appearance in Hong Kong after winning the Nobel was at CUHK; the University promptly held an exhibition titled "The Lore of a Laureate," showing the Nobel medal and diploma for the first time. According to a note beside the Gallery displays, the exhibition proved so popular that, originally scheduled to close in early spring, it was extended into that autumn; cumulative attendance ran into the tens of thousands. That level of enthusiasm says something about the medal's symbolic weight for the campus community. The medals subsequently moved from temporary special exhibition into the Gallery's permanent display, completing the transition "from a one-off appearance to a standing collection."

As for the two memorials on campus that students and staff pass far more often in daily life — the Charles Kuen Kao Building (the North Block of the Science Centre named in 1996) and the bronze statue unveiled outside the Ho Sin Hang Engineering Building in September 2010 — the full account of their naming, unveiling, sculptor and specifications is set out in charles-kao-vice-chancellor.md and will not be repeated here. What needs noting in this context is how each functions within the "Nobel memorial" narrative: the Kao Building is a quotidian, ever-present memorial of substance (a building where people go to class every day); the statue is a ceremonial, person-focused memorial (a likeness to stop and stand before); and the Nobel medal in the Gallery is a collected, close-at-hand piece of evidence (a genuine medal locked in a case). Three registers, together forming the campus's commemorative triad.

The journey of these medals from "private honour" to "public collection" is itself worth recording. Kao could well have kept the Nobel medal as a personal treasure, or donated it to any of the places where he grew up or worked. He chose instead to entrust the entire sequence of honours spanning half a century — the Nobel medal along with seventeen other major awards — to this University. For CUHK, the significance of these objects goes beyond "exhibits": they turn the abstract statement of institutional history — "CUHK appears on a Nobel laureate's list of affiliations" — into a physical artefact you can see through glass and point out to students. A genuine medal locked in a display case says more to each incoming cohort than any text: the bond between this University and that half-Nobel is real substance, not borrowed prestige.

One internal tension in the campus memorial is worth noting: Kao's foundational work of 1966 was done in Britain, and by the time he won in 2009 he had been out of the Vice-Chancellor's office for over a decade — yet the University can display that Nobel medal with every justification. The legitimacy rests precisely on the institutional listing. Because the Nobel committee wrote CUHK into Kao's affiliations, the University gained the right to bring the medal into its institutional history. The Gallery displays it alongside the other seventeen awards — not as "a single Nobel medal" but as the complete sequence of one engineer's lifetime honours, of which the Nobel is merely the brightest.

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# "Sparks from the Sand": what does the science park's 2025–2026 exhibition say?

Seven years after Kao's death (2018), the science park next door has mounted a new exhibition for him. According to Hong Kong Science Park's official event page^※, the memorial exhibition "Sir Charles K. Kao's Story: Sparks from the Sand" opened on 10 September 2025 on the ground floor of 10W at Hong Kong Science Park and runs until 31 December 2026 — a long-term exhibition lasting well over a year, not a brief anniversary event. The theme is built tightly around the image of Kao "making optical fibre out of sand," in direct descent from the "sand" in his Nobel lecture's title.

According to the same event page, the exhibition's purpose goes beyond retrospect; it aims to inspire. The official wording says the exhibition hopes to "inspire more innovators to embrace Sir Kao's pioneering spirit" and pursue "breakthrough discoveries and success." In other words, the science park has turned the Kao memorial into a piece of "spiritual teaching material" aimed at its own innovation and technology community. For a park whose mission is incubating tech start-ups, this orientation — "use a predecessor to spur on successors" — forms a subtle contrast with the University Gallery's bias towards "archival collection."

Placed back in the context of the "Golden Egg," the exhibition fills in the dynamic link in the park's commemoration of Kao. Until now, the park's tribute was primarily the static naming of the "Golden Egg" auditorium — an architectural landmark bearing his name. The "Sparks from the Sand" exhibition, by contrast, is an act of active curation, retelling Kao's story to the park's new generation of entrepreneurs. Naming inscribes a name into a building; curation tells a spirit to living people. With both in place, the park's commemoration of Kao has extended from "a building" into "a story still being told."

The information boundary is worth drawing: "Sparks from the Sand" is organised by Hong Kong Science and Technology Parks Corporation, with the venue at the science park rather than the CUHK campus. It is independent of, and runs in parallel with, the University Gallery's permanent Nobel medal display. For visitors, this means "seeing Kao" at Pak Shek Kok actually offers two itineraries — go into the CUHK campus for the genuine medal and the bronze statue in the University Gallery, or cross the wall into the science park for the "Golden Egg" and the "Sparks from the Sand" exhibition. The two itineraries are a stone's throw apart, yet belong to two institutions.

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# How does the fibre laureate's Nobel legacy live on, at CUHK and at Pak Shek Kok?

When Kao came to CUHK in 1970 to build the Department of Electronics, fibre-optic communication was still a paper assertion in a laboratory. By the time he died in 2018, the fibre supporting the global internet had been laid beneath land and sea. That arc — "from one paper to the world's infrastructure" — has left two kinds of continuation on this stretch of Pak Shek Kok land: one is the continuation of a research agenda, the other the continuation of an innovation ecosystem.

On the research side, Kao's core idea of "carrying information with light" remains an active frontier in CUHK's engineering faculties, not merely an exhibit for display. According to public records in the CUHK research repository^※, the Faculty of Engineering has continued to produce results in photonics and fibre optics in recent years, covering applied topics such as precision fibre-optic alignment and packaging and tunable optical delay. At a moment when data explosions and AI data centres are driving an explosion in demand for transmission bandwidth, making light travel faster and more efficiently through fibres and photonic chips remains the central battleground of optical communications research worldwide. Kao's approach to pushing attenuation below 20 dB/km — working from materials and structure, approaching physical limits — is still the methodological bedrock of the field.

On the ecosystem side, we return to the "Golden Egg." The Hong Kong Science Park that Kao campaigned to establish is now the core vehicle of Hong Kong's innovation and technology sector, and the auditorium that bears his name is one of the most regularly used stages in the park for technology forums, launches and academic events. According to Science Park event materials^※, the park casts Kao as a symbol of the "pioneering spirit" that entrepreneurs are encouraged to emulate. Kao's name thus has two "uses" at Pak Shek Kok. At CUHK, it is a teaching building, a bronze statue, a Nobel medal under glass — pointing to achievement completed. At the science park, it is a lecture hall where people meet daily, an exhibition urging entrepreneurs on — pointing to a future still unfolding. The two uses do not conflict; they complement each other. The university's job is to keep a predecessor's achievements safely collected and available for contemplation; the park's job is to translate the same predecessor's spirit into a summons to those who come after. Perhaps the best way to honour a person is precisely to do both — to remember what he did and to urge others to carry it on. The memorials to Kao on the two shores of the water at Pak Shek Kok happen to assign those two tasks respectively to the university and the park.

According to the Hong Kong Laureate Forum^※, Kao once described his motto: "After my passing away, I would have left a mark on the world, like footprints in the sand." Read alongside his Nobel lecture's title, the two statements close a satisfying loop. His life's work was to purify the most humble of materials — sand (silica sand, the raw ingredient of glass) — into optical fibre that carries the human voice; and the aspiration he set himself was to leave footprints in the sand. Sand is at once his raw material and the image on his epitaph.

In that sense, the answer to "how does CUHK commemorate Charles Kao" extends beyond the University's walls: the Nobel medal is locked in the University Gallery, the "Golden Egg" stands in the science park just past the wall, and his truest and widest memorial — invisible to all — is every single fibre-optic cable now carrying light: a hidden monument distributed across the globe that no one could ever fully count. According to CUHK Communications and Public Relations Office's memorial article^※, the University, mourning his passing, summarised his bond with CUHK as one word: "home." He attended secondary school in Hong Kong, served as Vice-Chancellor of CUHK, and retired in Hong Kong. This stretch of land was both the starting point of his career and his final resting place.

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# See also

• Charles Kao and CUHK: A Complete File — From Founding the Electronics Department to Nobel-President (1970–2018) — the full record of Kao's department-founding, vice-chancellorship, statue and scholarships
• Distinguished Scholars Affiliated with CUHK (Nobel Prize / Fields Medal / Turing Award) — the grading of affiliation strength between "achievement listed under CUHK" and "Distinguished Professor-at-Large"
• Profiles of Notable Professors, Academic Leaders and Figures at CUHK — portraits of past Vice-Chancellors and masters of their fields

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