Awarded entry of the HKIE 50th Anniversary Legacy Award (Innovation Category): “Fibre Optic - Revolutionary Change in Modern Telecommunications By Professor Charles K. Kao”

The HKIE proudly honours Prof Charles Kao Kuen (4 November 1933 – 23 September 2018) with its 50th Anniversary Legacy Award in the Innovation Category, recognising the renowned physicist and Nobel laureate’s groundbreaking contributions to modern telecommunications. Voted by the public as the most outstanding innovation project among several shortlisted projects over the past five decades, Prof Kao’s pioneering work in fibreoptics has reshaped how the world communicates — laying the very foundations for the Internet age. His vision and scientific insight earned him the title “Father of Fibre Optics”, and his work continues to impact how people around the world connect, learn and share information today.

A visionary ahead of his time

As early as 1966, Prof Kao, in collaboration with George Hockham, proposed the revolutionary theory that light signals could be transmitted over long distances with minimal loss through ultra-pure glass fibres using the principle of total internal reflection. This vision challenged prevailing skepticism, because at that time optical fibres suffered from high signal loss (around 200 dB/km), making them unfit for practical use.

Prof Kao theorised that if impurities — particularly metal ions — could be drastically reduced, signal loss would be minimised, making fibre optics viable for communication. He also proposed a core-cladding structure with a refractive index difference of about 1%, enabling the transmission of light in a single mode with high capacity. His belief that “the crucial material problem appears to be one which is difficult but not impossible” would catalyse a global shift in communications research.

Prof Charles K Kao

Breaking through the barriers

The road to realising Prof Kao’s vision was fraught with challenges. In the 1960s, no commercially available glass was pure enough, and significant resistance existed from the scientific community, which doubted that fibre optics could outperform the favoured traditional copper wires and millimeter waveguides. Prof Kao’s work demanded not just theoretical breakthroughs but also novel engineering techniques, from precise fibre drawing to durable coating methods, reliable light source development and measurement of the optical loss of highly transparent materials.

Yet Prof Kao persisted. Throughout the 1970s, his continued research contributed to practical advancements. His leadership and technical insight spearheaded advancements in fibre design and manufacturing techniques that led to low-loss fibres. His ongoing work helped to realise the vision he had laid out in 1966. The fibres developed later allowed signals to travel much further before the need to be amplified. Prof Kao’s commitment finally culminated in a historic achievement in 1981: the development of the first commercial fibre optic communication system. Fibre optics could practically replace the traditional copper wire, bringing a breakthrough in communication technology.

This success validated decades of perseverance and ushered in a new era of global communication.

Impact that has transformed the world

Prof Kao’s contributions cannot be overstated. Fibre optics fundamentally changed the way we communicate, by offering vastly greater bandwidth that enables the transmission of more data, lower interference due to immunity to electromagnetic interference, longer transmission distances, and smaller lighter cables than copper cables. From the rise of high-speed Internet and streaming media to real-time global connectivity, Prof Kao’s work paved the way for the modern information economy.

The ability of fiber optics to carry large volumes of data at ultra-fast speeds and with exceptional reliability has made it the backbone of high-speed telecommunications networks around the world. Fiber optics is clearly much more than just a means of data transmission; it is the foundation on which the future of communications has been built, driving information exchange, collaboration and advancement in all areas of society.

The most significant technological advances since Prof Kao’s initial contributions include:

• Single-Mode Fibre, which allows only one path for light, reducing signal dispersion, enabling higher bandwidth and even longer-distance communication.
• Erbium-Doped Fibre Amplifiers (EDFAs), which amplify optical signals without converting them to electrical signals, thereby extending the reach of fibre optic systems.
• Wavelength-Division Multiplexing (WDM), which allows multiple optical signals to be transmitted simultaneously over a single fibre, dramatically increasing the capacity.
• Coherent optical communication combined with advanced digital signal processing has enabled enhanced data rates and spectral efficiency.
• Photonic Integrated Circuits (PICs), which integrate multiple optical functions onto one chip, thereby reducing size, cost and power consumption.
• Hollow-core fibres, which allow even greater optical speed and power handling than a single-mode fibre.

A lasting legacy in science and society

Beyond his technical brilliance, what set Prof Kao apart was his decision not to patent the fibre optic technology, allowing its free adoption and universal benefit. He opened up the technology so that fibre optic communication and the Internet could be popularised for the benefit of humankind.

His work has empowered everything from international commerce to digital education, healthcare and beyond. He revolutionised communication by enabling the Internet, high-speed data networks and global connectivity. Without fibre optics, the modern information age would have been impossible. We can now transmit vast amounts of data (voice, video, text) across the world almost instantaneously.

The global community has continued to celebrate Prof Kao’s legacy. In 2009, he was awarded the Nobel Prize in Physics. He also received the Order of the British Empire (OBE) and the National Medal of Science. These accolades highlight his profound impact on technology and science. Additionally, universities and other institutes commemorate his life and work through lectures and scholarships; his name graces buildings and lecture halls, including the Charles K. Kao Auditorium at the Hong Kong Science Park and the Charles Kuen Kao Building at The Chinese University of Hong Kong, where he was Vice-Chancellor from 1987 to 1996.

Prof Kao (R) and Mrs Kao

Following Prof Kao’s passing in 2018, events and tributes have been organised to celebrate his legacy and the profound influence he had on modern technology. These efforts collectively ensure that Prof Kao’s legacy continues to inspire and influence both the technical community and the general public.

Prof Kao’s foundational work remains the cornerstone of optical communications research. His groundbreaking research continues to be cited extensively in scientific literature, with many researchers building upon his legacy in fibre optics and communications technology. His influence on current research includes exploring ultra-low-loss fibres with higher bandwidth, advanced modulation techniques to increase data load through existing fibres, developing more efficient compact optical amplifiers and components for fibre optic systems, plus even developing quantum communication technologies enabled by fibre optics.

Having grown up in Hong Kong and making Hong Kong his home in later life, Prof Kao has been the pride of Hong Kong and the Chinese community. His global achievements and contributions, as well as his pioneering spirit and passion, continue to inspire innovators and to impact researchers around the globe. His story is a powerful reminder of the enduring impact of engineering innovation and the importance of bold thinking, rigorous science, and humanistic vision.

The recognition received by “Fibre Optic - Revolutionary Change in Modern Telecommunications By Professor Charles K. Kao”, as the awarded entry of the HKIE 50th Anniversary Legacy Award (Innovation Category), reflects the deep societal gratitude for his impactful achievements. More than an engineer, he was a visionary whose contributions not only advanced science but also united the world through communication. Optical fibre communication remains one of the most transformative inventions of the 20th century, and this award rightly honours its profound influence on engineering and society, not only in Hong Kong but the entire world.

Dr William Lo Wing Yan, Founding Governor and Chairman of the Charles K Kao Foundation for Alzheimer's Disease (middle) receiving of the HKIE 50th Anniversary Legacy Award (Innovation Category) from the President for Session 2024/2025 Ir Eric Ma (2nd left), Secretary for Development Ms Bernadette Linn (1st left), Secretary for Housing Ir Winnie Ho (2nd right), and Secretary for Innovation, Technology and Industry Ir Prof Sun Dong (1st right)