First, it was
Jagadish Chandra Bose at the turn of the century, who was the first to
demonstrate wireless signaling in 1895. Later, he even created a radio
wave receiver called the 'coherer' from iron and mercury. Though he
showed no interest in patenting it, Bose demonstrated his inventions in
Kolkata and London.
Sir
Neville Mott, who won the Nobel Prize for Physics in 1978, in fact
commented that Bose had foreseen the 'n' and 'p' type semiconductors,
and was 'sixty years ahead of his time.' However, the Nobel Prize in
Physics for wireless communication was awarded to Guglielmo Marconi in
1909, 14 years after Bose had demonstrated the possibility. Then came Satyendranath Bose, who sent a paper on the statistics of quanta of light–photons to Albert Einstein. Einstein supported the paper and got it published in Zeitschrift der Physik
in 1924, and that in turn gave birth to the now famous Bose-Einstein
statistics and the term 'Bosons' for all those elementary particles that
follow it.Even though three Nobel Prizes have been awarded for works based
on Bose statistics, the originator of the idea was never awarded one. Moving on, G N Ramachandran deserved a Nobel for his work on
bio-molecular structures in general and, more particularly, the triple
helical structure of collagen. E C George Sudarshan produced pioneering
contributions to Quantum Optics and coherence, but his work was ignored,
and Roy Glauber was awarded the Physics Nobel in 2005 for the same
work.
And so to this week: The press release issued by The Royal
Swedish Academy of Sciences on the Nobel Prize for Physics for 2009 says
'one half' of the prize has been awarded to Charles K Kao 'for
groundbreaking achievements concerning the transmission of light in
fibers for optical communication.' What the Academy omitted to note was that Moga, Punjab-born
Narinder Singh Kapany, widely considered the Father of Fibre Optics,
and, in this capacity, featured in a 1999 Fortune magazine article on the 'Unsung Heroes of the 20th Century', had far the stronger claim. Charles Kao in a 1996 paper put forward the idea of using glass
fibres for communication using light; he tirelessly evangelised it and
fully deserves a share of the Prize. However, the fact remains that it
was Kapany who first demonstrated successfully that light can be
transmitted through bent glass fibres during his doctoral work at the
Imperial College of Science in London in the early fifties, and
published the findings in a paper in Nature in 1954. Since then, Kapany irelessly developed applications of fibre
optics for endoscopy during the fifties and later coined the term Fibre
Optics in an article in Scientific American in 1960. His body of work provided the basis for the developments of any and all applications in communications.
In a book published in 2003 by Rupa & Co titled Sand to Silicon: The Amazing Story of Digital Technology,
I had written of the respective contributions of Kapany and Kao to the
field of Fiber Optics. A relevant excerpt (pages: 154-159): Very few Indians know that an Indian,
Narinder Singh Kapany, a pioneer in the field, coined the term (Fibre
Optics) in 1960. We will come to his story later on, but before that let
us look at what fibre optics is. It all started with queries like: Can
we channel light through a curved path, even though we know that light
travels in a straight line?' Why is that important? Well, suppose you want to examine an
internal organ of the human body for diagnostic or surgical purposes.
You would need a flexible pipe carrying light. Similarly, if you want to
communicate by using light signals, you cannot send light through the
air for long distances; you need a flexible cable carrying light over
such distances.'The periscopes we made as class projects when we were in school,
using cardboard tubes and pieces of mirror, are actually devices to
bend light. Bending light at right angles as in a periscope was simple.
Bending light along a smooth curve is not so easy. But it can be done,
and that is what is done in optic fibre cables.''For centuries people have built canals or viaducts to direct
water for irrigation or domestic use. These channels achieve maximum
effect if the walls or embankments do not leak.' 'Similarly, if we have a pipe whose insides are coated with a
reflecting material, then photons or waves can be directed along easily
without getting absorbed by the wall material.'
'A light wave gets reflected millions of times inside such a pipe
(the number depending on the length and diameter of the pipe and the
narrowness of the light beam).'
'This creates the biggest problem for pipes carrying light. Even
if we can get coatings with 99.99 per cent reflectivity, the tiny
'leakage' of 0.01 per cent on each reflection can result in a near-zero
signal after 10,000 reflections.''Here a phenomenon called total internal reflection comes to the
rescue. If we send a light beam from water into air, it behaves
peculiarly as we increase the angle between the incident ray and the
perpendicular.'
'We reach a point when any increase in the angle of incidence
results in the light not leaving the water and, instead, getting
reflected back entirely. This phenomenon is called total internal
reflection.'
'Any surface, however finely polished, absorbs some light, and hence repeated reflections weaken a beam.'
'But total internal reflection is a hundred per cent, which means
that if we make a piece of glass as non-absorbent as possible, and if
we use total internal reflection, we can carry a beam of light over long
distances inside a strand of glass.'
'This is the principle used in fibre optics.'
'The idea is not new. In the 1840s, Swiss physicist Daniel
Collandon and French physicist Jacques Babinet showed that light could
be guided along jets of water.'
'British physicist John Tyndall popularised the idea further
through his public demonstrations in 1854, guiding light in a jet of
water flowing from a tank.'
'Since then this method has been commonly used in water
fountains. If we keep sources of light that change their colour
periodically at the fountainhead, it appears as if differently coloured
water is springing out of the fountain.'
'Later many scientists conceived of bent quartz rods carrying light, and even patented some of these inventions. But it took a 
long
time for these ideas to be converted into commercially viable products.
One of the main hurdles was the considerable absorption of light inside
glass rods.'
'Narinder Singh Kapany recounted to the author, "When I was a
high school student at Dehradun in the beautiful foothills of the
Himalayas, it occurred to me that light need not travel in a straight
line, that it could be bent. I carried the idea to college. Actually it
was not an idea but the statement of a problem. When I worked in the
ordnance factory in Dehradun after my graduation, I tried using
right-angled prisms to bend light.'
'However, when I went to London to study at the Imperial College
and started working on my thesis, my advisor, Dr Hopkins, suggested that
I try glass cylinders instead of prisms. So I thought of a bundle of
thin glass fibres, which could be bent easily. Initially my primary
interest was to use them in medical instruments for looking inside the
human body. The broad potential of optic fibres did not dawn on me till
1955. It was then that I coined the term fibre optics."'
'Kapany and others were trying to use a glass fibre as a light
pipe or, technically speaking, a 'dielectric wave guide'. But drawing a
fibre of optical quality, free from impurities, was not an easy job.
Kapany went to the Pilkington Glass Company, which manufactured glass
fibre for non-optical purposes. For the company, the optical quality of
the glass was not important.'
'"I took some optical glass and requested them to draw fiber from
that," says Kapany. "I also told them that I was going to use it to
transmit light. They were perplexed, but humoured me."'
'A few months later Pilkington sent spools of fibre made of green
glass, which is used to make beer bottles. "They had ignored the
optical glass I had given them. I spent months making bundles of fibre
from what they had supplied and trying to transmit light through them,
but no light came out. That was because it was not optical glass. So I
had to cut the bundle to short lengths and then use a bright carbon arc
source."'
'Kapany was confronted with another problem. A naked glass fibre
did not guide the light well. Due to surface defects, more light was
leaking out than he had expected. To transmit a large image he would
have needed a bundle of fibres containing several hundred strands; but
contact between adjacent fibers led to loss of image resolution.'
'Several people then suggested the idea of cladding the fibre.
Cladding, when made of glass of a lower refractive index than the core,
reduced leakages and also prevented damage to the core. Finally, Kapany
was successful; he and Hopkins published the results in 1954 in the
British journal Nature.'
'Kapany then migrated to the US and worked
further in fibre optics while teaching at Rochester and the Illinois
Institute of Technology. In 1960, with the invention of lasers, a new
chapter opened in applied physics. From 1955 to 1965 Kapany was the lead
author of dozens of technical and popular papers on the subject. His
writings spread the gospel of fibre optics, casting him as a pioneer in
the field.'
'His popular article on fibre optics in Scientific American
in 1960 finally established the new term (fibre optics); the article
constitutes a reference point for the subject even today. In November
1999, Fortune magazine published profiles of seven people who
have greatly influenced life in the twentieth century but are unsung
heroes. Kapany was one of them.'
'If we go back into the history of modern communications
involving electrical impulses, we find that Alexander Graham Bell
patented an optical telephone system in 1880. He called this a
'photophone'. Bell converted speech into electrical impulses, which he
converted into light flashes.'
'A photosensitive receiver converted the signals back into
electrical impulses, which were then converted into speech. But the
atmosphere does not transmit light as reliably as wires do; there is
heavy atmospheric absorption, which can get worse with fog, rain and
other impediments.'
'As there were no strong and directional light sources like
lasers at that time, optical communications went into hibernation.
Bell's earlier invention, the telephone, proved far more practical. If
Bell yearned to send signals through the air, far ahead of his time, we
cannot blame him; after all, it's such a pain digging and laying
cables.'
'In the 1950s, as telephone networks spread, telecommunications
engineers sought more transmission bandwidth. Light, as a carrying
medium, promised the maximum bandwidth. Naturally, optic fibres
attracted attention. But the loss of intensity of the signal was as high
as a decibel per metre.'
'This was fine for looking inside the body, but communications
operated over much longer distances and could not tolerate losses of
more than ten to twenty decibels per kilometre. Now what do decibels
have to do with it? Why is signal loss per kilometre measured in
decibels?'
'The human ear is sensitive to sound on a logarithmic scale; that
is why the decibel scale came into being in audio engineering, in the
first place.'
'If a signal gets reduced to half its strength over one kilometre
because of absorption, after two kilometres it will become a fourth of
its original strength. That is why communication engineers use the
decibel scale to describe signal attenuation in cables.'
'In the early 1969s signal loss in glass fiber was one decibel
per metre, which meant that after traversing ten metres of the fiber the
signal was reduced to a tenth of its original strength.'
'After twenty metres the signal was a mere hundredth its original
strength. As you can imagine, after traversing a kilometre no
perceptible signal was left.'
'A small team at the Standard Telecommunications Laboratories in
the UK was not put off by this drawback. This group was headed by Antoni
Karbowiak, and later by a young Shanghai-born engineer, Charles Kao.'
'Kao studied the problem carefully and worked out a proposal for
long-distance communications through glass fibres. He presented a paper
at a London meeting of the Institution of Electrical Engineers in 1966,
pointing out that the optic fibre of those days had an
information-carrying capacity of one GHz, or an equivalent of 200 TV
channels, or more than 200,000 telephone channels.'
'Although the best available low-loss material then showed a loss
of about 1,000 decibels/kilometre (dB/km), he claimed that materials
with losses of just 10 to 20 dB/km would eventually be developed.'
'With Kao almost evangelistically promoting the prospects of
fibre communications, and the British Post Office (the forerunner to
British Telecom) showing interest in developing such a network,
laboratories around the world tried to make low-loss fibre. It took four
years to reach Kao's goal of 20dB/km.'
'At the Corning Glass Works (now Corning Inc), Robert Maurer,
Donald Keck and Peter Schultz used fused silica to achieve the feat. The
Corning breakthrough opened the door to fibre-optic communications. In
the same year, Bell Labs and a team at the Ioffe Physical Institute in
Leningrad (now St Petersburg) made the first semiconductor lasers, able
to emit a continuous wave at room temperature.'
'Over the next several years, fibre losses dropped dramatically,
aided by improved fabrication methods and by the shift to longer
wavelengths where fibers have inherently lower attenuation.'
'Today's fibres are so transparent that if the Pacific Ocean,
which is several kilometres deep, were to be made of this glass we could
see the ocean bed!'
'Note one point here. The absorption of light in glass depends
not only on the chemical composition of the glass but also on the
wavelength of light that is transmitted through it. It has been found
that there are three windows with very low attenuation: One is around
900 nanometres, the next at 1,300 nm and the last one at 1,550 nm.'
'Once engineers could develop lasers with those wavelengths, they
were in business. This happened in the 1970s and 1980s, thanks to
Herbert Kroemer's hetero-structures and many hard-working
experimentalists.'
The excerpt ends here. While working on this book and
particularly this chapter, I had thought that with the world now firmly
ensconced in the era of communications, it wouldn't be long before
Narinder Kapany's pioneering work in the field was recognised with the
Nobel Prize.
Now, two years later, I find that the name of the pioneer of
fibre optics has been added to a very long list of Indians who, though
richly deserving of the ultimate accolade, the Nobel Prize, have been
mysteriously passed over by the august members of the Royal Swedish
Academy of Sciences.
sumber: http://www.rediff.com/news/report/how-india-missed-another-nobel-prize/20091008.htm
