Photonics researchers nab 2009 Nobel in Physics

STOCKHOLM, SWEDEN--The Nobel Prize in Physics for 2009 was awarded for two scientific achievements, both in photonics, which have shaped the foundations of today’s information society: long-distance fiber-optic transmission, and CCD arrays.

STOCKHOLM, SWEDEN--The Nobel Prize in Physics for 2009 was awarded for two scientific achievements, both in photonics, which have shaped the foundations of today’s information society: long-distance fiber-optic transmission, and CCD arrays. In a way, the two inventions are synergistic. Long-distance optical fiber has tied the world together and allowed it to share vast amounts of information, transmitted around the globe with little delay, while CCD cameras have served to produce much of that data, some of it in the form of still images and much in the form of video (it has been said that the majority of data transmitted via the Internet is image-related).

The prize was awarded in three parts: one-half went to Charles K. Kao (Standard Telecommunication Laboratories, Harlow, England, and Chinese University of Hong Kong) for his work on ultra-pure optical fiber, while the other half was divided equally between Willard S. Boyle and George E. Smith (Bell Laboratories, Murray Hill, NJ), who developed the first CCD sensor. The award amounts to 10 million Swedish kronor (about $ 1.4 million) and was divided among the three Nobel laureates in proportion to the prize portions.

Practical fiber optics

In 1966, Kao made a discovery that led to a breakthrough in fiber optics. While optical fiber had previously been proposed as a medium for optical communications, the fiber of the time was so lossy that it could only transmit signals a few tens of meters. Kao determined that, by using extremely pure silica for optical fibers, it would be possible to transmit light signals over a distance of 100 kilometers. Such a distance was long enough to turn optical fiber from a laboratory curiosity into a practical high-speed communications medium.

Kao’s enthusiasm inspired other researchers, and the first ultrapure fiber was successfully fabricated just four years later, in 1970, at Corning Glass Works (Corning, NY). Today’s global fiber-optic network contains more than one billion kilometers of fiber.

Digital imaging

In 1969, Boyle and Smith invented the first successful imaging technology that used a digital sensor: a charge-coupled device (CCD), which makes use of the photoelectric effect, as theorized by Albert Einstein (and for which Einstein was awarded the 1921 Nobel Prize). By this effect, light is transformed into electrical signals. The challenge when designing a CCD image sensor was to gather and read out the signals from a large number of pixels in a short time.

The first commercial CCD sensor was developed at Fairchild Imaging (Milpitas, CA); the device was a 500 pixel linear array. The CCD soon became a standard for astronomical imaging, and went on from there to supersede film-based still and motion-picture cameras, as well as tube-type video cameras. The other type of common digital imager, the CMOS camera, came into use years later, because CMOS arrays required more advanced fabrication equipment than was available when CCDs first came into use.

Charles Kao was vice-chancellor at the Chinese University of Hong Kong before he retired in 1996. Willard Boyle was executive director of Bell Labs’ Communication Sciences Division; he retired in 1979. George Smith, who was head of the VLSI Device Department at Bell Labs, retired in 1986.

--John Wallace

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