Transcript Slides - Agenda INFN

The 2009 Nobel Prize for Fibre
Optics and its Origins
Hypolito José Kalinowski
National Institute of Photonics Science and Technology for
Optical Communications – UTFPR Branch
2
One fibre to bring them all and in the brightness bind
them
J.R.R. Tolkien, The Lord of the Rings
– adapted by the author
3
FOTONICOM

Brazilian Research Council (CNPq) funded
institute for Photonics & Optical
Communications
 Head Institute: State University of Campinas
(UNICAMP)
 10 Research Groups
 ~ 40 faculty
 ~ 120 students & pos-doc
4
Outline
•
•
•
Electromagnetic Aspects
Materials Aspects
Putting all together
•
B.K. (Before Kao)
5
2009 Nobel Prize in Physics
Charles Kuen Kao
The 2009 Nobel Prize in Physics honors three scientists, who have had
important roles in shaping moder information technology, with one half
to Charles Kuen Kao and with Willard Sterling Boyle and George
Elwood Smith sharing the other half. Kao’s discoveries have paved the
way for optical fiber technology, which today is used for almost all
telephony and data communication. ...
K. C. Kao, G. A. Hockham (1966), "Dielectric-fibre surface waveguides for optical frequencies", Proc. IEE 113 (7):
1151–1158
6
Once upon a time... (?)
7
James Clerk Maxwell
The Royal Society of Edinburgh, George Street, 07 Oct 2009
8
Electromagnetism before 1864

E 
0
B  0
B
 E  
t
  B  0 J

Gauss Law

Non-existing magnetic
monopoles

Faraday’s Law

Ampere’s Law
9
Electromagnetism before 1864
B
 E   
t
  B
     0  
0
t
    B   0  J
  
0  0  

 t 
  constant

Taking the divergence
That’s OK.
 Repeating
 Correct for J constant,
but ...
 Electrodinamics, charge
conservation
 For all space!!! ???

10
Maxwell Equations
D  
B  0
B
 E  
t
D
 H  J 
t
Army’s Institute of Engineering Library (Rio de Janeiro)
http://trailblazing.royalsociety.org/
J.C. Maxwell, “On physical lines of force”, Phil. Mag., 161ff, 1861
11
Light as an Electromagnetic Wave

Transversal oscilations
in the same E.M.
Medium.

Velocity of propagation
c 1

 0 0
J.C. Maxwell, “On physical lines of force”, Phil. Mag., 161ff, 1861
Part III: The Theory of Molecular Vortices applied to Static Electricity
Original agreement
~ 1,4%
J.C. Maxwell, “A Dynamical Theory of the Electromagnetic Field ”,
Phil. Trans. Royal Soc., 155, 459ff, 1865 (8 Dec 1864)
12
Helmholtz Equation
Propagation
2
2

E

P
2
    E   E   0  0 2   0 2
t
t
1
Used by Maxwell, “A Dynamical...”, op. cit.
c
 0 0
E ( x, y, z , t )  E ( x, y )e i ( z t )
 2 E ( x , y )  [  2   2  0 0 ] E ( x , y )  0
13
Eletromagnetism after Maxwell

Free Space Eletromagnetism

Linear, isotropic, dispersionless medium, free
of charges or currents

Elementary solutions based on propagating
harmonic waves (superposition).
14
Free Space Electromagnetic
Propagation

Electromagnetic waves
 Wireless telegraphy
 Radio
 Television
 Communication satellites
 Microwave links
 Wireless & mobile communications
15
Eletromagnetism after Maxwell

Eletromagnetism in material media
 Polarization (P) and Magnetization (M)
D   0 E  P  (1   e ) 0 E  E
B  0 ( H  M )  (1   m ) 0 H  H

Non linear, anisotropic, dispersive media
 Solutions based in harmonic propagating waves
(superposition  wave packets)
16
Dielectric Waveguides

Limits and discretization of solutions
– Fundamentally derived from boundary conditions for
the electromagnetic fields
– Guided modes
– Leaky modes

Characteristic equation for modal solutions
– Determines modal field patterns & associated
parameters
– Dispersion relation

Interest for optics: frequency region where only
one mode can propagate – singlemode waveguide
17
Optical Spectrum
193
Frequency
Wavelength
(vacuum)
Longhaul Telecom
Regional Telecom
Local Area Networks
229
353
461
THz
Near infrared
1.8
1.6
1.4
1.2
UV
1.0
0.8
0.6
0.4
HeNe Lasers
633 nm
1550 nm
CD
780 nm
1310 nm
850 nm
0.2
µm
18
Optical Waveguide
19
Fibre Optics (after Kao)

Made from Silica (SiO2).
 Silica is the most abundant material on Earth’s
surface.
 Reduction of impurities and fabrication
imperfections.
 Silica obtained from Quartz powder, because it
has less impurities than common sand.
20
Once upon a time... ( again !?)
21
Glass and its Benefits

(Accidental ?) Discovery about 2500 BC
 Egypt (pots), Syria (blown glass), Assiria (first
‘manual’ ~650BC)
 Spread with Fenitian, Roman, Venetian
 Venice became the principal source of glass in
13th century
– Pots, bottles, tubes, flat glass, mirrors, ...

Glass changed society at the end of the
Medioevo, Renaissance and beggining of
Modern age
22
A World of Glass
A. Macfarlane & G. Martin, Science 305 (5689), 1407, 2004

Glass in Science
– Widespread applications
in all Science areas
– Instruments
– Fundamenal experiments

Glass in dayly use
– Windows (light,
cleaning)
– Commerce (exhibit,
storage, transport)
– Greenhouses
23
There are many other useful applications of glass that altered everyday life from
the 15th century onward. Among them were storm-proof lanterns, enclosed
coaches, watch-glasses, lighthouses, and street lighting. The sextant required
glass, and the precision chronometer invented by Harrison in 1714, which
provided a solution to calculating longitude at sea, would not have been possible
without glass. Thus, glass directly contributed to navigation and travel. Then,
there was the contribution of glass bottles, which increasingly revolutionized the
distribution and storage of drinks, foods, and medicines. Indeed, glass bottles
created a revolution in drinking habits by allowing wine and beer to be more
easily stored and transported. First through drinking vessels and windows, then
through lanterns, lighthouses, and greenhouses, and finally through cameras,
television, and many other glass artifacts, our modern world has emerged from a
sea of glass.
The different applications of glass are all interconnected--windows improved
working conditions, spectacles lengthened working life, stained glass added to
the fascination and mystery of light and, hence, a desire to study optics. The rich
set of interconnections of this largely invisible substance have made glass both
fascinating and powerful, a molten liquid that has shaped our world.
24
Glass Fibres

Made by Egiptians ~1600 A.C
– Fibre decorated potery dated ~1375 AC


External fiber decorated glass cups, Venice
Reamur (1700´s): glass fibres
– Fibres as this as spider´s web threads would be flexible and
could be tecelagem

XIX Century: glass fibres and cloths for
decorative purposes
 C.V. Boys (1887): ‘elastic’ fibre ~2,5μm
– Glass  quartz (silica) [as resistants as steel wires]
– Scientific apparatus at end of 19th century and begining of
20th (torsion balance, balistic galvanometers, e.g.)
25
Light Guiding

Total internal refraction
 Light beams guided in
water jets
 Popular shows during
second half of 19th
century
– J. Tyndall
D. Collandon “On the reflectivity of a
ray of light inside a parabolic liquid
stream” Comptes Rendus 15, 800802, 1842.
26
Dissemination ?
27
Fibre Imaging

Light transmission in
fibres
– Illumination
(Odontology, Medicine)

Lucite rods
– Imaging (Endoscopy)


Fibre bundles
Image transmission
– Television


Fibre bundles
High losses on surfaces
and bends
H. Lamm, Zeitsch. Instrumentenkunden, 579, 1930
28
Fibre Optics – 1950’s-1960’s



Losses in bundles due to fibre contact
Needed to avoid surface losses
Metallic deposition on surface
– Still high losses
99% reflector, 100 reflections 36,6% lost
> 1000 reflections per meter of fibre

Cladding with lower refractive index material
– Total internal reflection inside fibre
– Dielectric materials



Honey, margarine, cooking (olive ?) oil
Plastic fibres cladded with bee’s wax
Plastic cladded glass fibres
A.C.S. Van Heel, Die Ingenieur 24(12), 1953
Nature 173, 39, 1954
29
30
Fibre Imaging

H. Hopkins & N.S. Kapany
– Gastric endoscope
H. Hopkins & N.S. Kapany,
Nature 173, 39-41, 1954
– Fibre bundles (1000+), l =75 cm

B. Hirschowitz & L. Curtiss
– Drawing of high refractive index glass fibres
– Glass cladded fibres (Curtiss)
 8 km/hr, “low” atenuation, external jacket
 40.000 fibre bundles
L.E.Curtiss, Glass fibers optical devices, US
Patent 3589793, dep. 1957, conc. 1971.
B. Hirschowitz, Gastroenterology 35, 50-53,
1958
31
Curtiss’ Process

Curtiss introduced the
preforma concept
– Concentric rods of high/low
High n
Low n
refractive index

Basically it is the process
currently used
– Several methods to obtain the
preforma
– Fundamental for
microstructured fibres

Endoscopes disseminated
during ’60 of century XX
– Gastroenterology
– Industrial use (inspection)
32
Fibre Optics before Kao








Luminous Fountains
Glass fibres for industrial use (thermal insulation, e.g.)
Glass or plastic illuminators
Optical card readers
Cryptography (bundle scrambling)
Gastroenteroscopes
Endoscopes & surgery illuminators
Image intensifiers faceplates
Basically limited to short lenghts (~ m) due to high glass losses and bend
losses during normal use
33
Lasers (1958-1966)

Optical frequencies carrier
– Increase in channel number (FDM)

High fluence
– Long distance links, free space direct links

Heterostructure semiconductor laser
– CW operation at room temperature
– Low electrical power
– Small devices

Proposition (& testing) of confined beams (mirros, lenses) in
burried pipes, direct links
– High sensitivity to temperature and environmental conditions
34
Fibre Optics for Communications

Study of factors
contributing to loss
– Atenuation due to
impurities, chemical
structure, light scattering
and geometrical
imperfections in the
glass

Possible use in optical
links
 a < 20 dB/km
– ~ 1GHz
K. C. Kao, G. A. Hockham (1966), "Dielectric-fibre surface waveguides for
optical frequencies", Proc. IEE 113 (7): 1151–1158
35
Kao & Hockham
36
LP01
TE02, TM02
HE12 + EH11
EH + HE
LP21
LP11
LP12
• Literature review
• Analysis of properties, several
materials
• Methodology
• Theory
• Experiments
• Model comparison
• Results & Discussion
• Proposition & Conclusions
37
Conclusions – Kao & Hockham
–
–
–
–
–
–
–
–
Practical optical guide, F
~100 lo
Flexíble, mec. tol. ~10%
ncore - nclad ~1%
Singlemode HE11
Information capacity > 1
GHz
Probable advantage in cost
(coaxial, radio)
Dielectric with low loss
Required loss < 20dB/km
(fundamental involved limits
much lower)
Fibras da época ~1000 dB/km (melhoria de 1098 !!)
38
Fibres just after

Small laboratory demos
– Video transmission with bundle of 70, 20m long,
fibras (1 dB/m) (1967)

Search for low loss glasses
– Several visits to Bell, American Optics, Corning,
Bausch & Lomb, ... (Kao)

Graded index fibres (Japan)
39
Ultra pure Glass Fibre Optics

Loss measurements in optical glasses ( l ~ 30
cm)
– Differential spectrometry ( Dl = 20 cm)

Fused silica losses
– (< 1ppm impurities)
– < 5 dB/km
K.C. Kao & T.W. Davies (1968), “Spectrophotometric studies of ultra low loss
optical glasses 1:single beam method", J. Sci. Instrum.: 331-335
M.W. Jones & K.C. Kao (1969), “Spectrophotometric studies of ultra low loss
optical glasses 2:double beam method", J. Sci. Instrum.: 331-335
 Possible to purify optical glasses to obtain required loss !
40
6 years conquist


Glass purifying
Double crucilble process (already used in past)
– Dyot (sugar molasses optimization)

Flame photolysis (Corning)
F.P. Kapron, D.B. Keck & R.D. Maurer, “Radiation losses in glass
– Fibre SiO2/SiO2:Ti
optical waveguides”, Appl. Phys. Letters 17, 423-425, 1970
– Scattering loss ~ 7 dB/km
– “Lowest value of total loss among all used waveguide was
approximately 20 dB/km”
– British Post Office measurements confirmed 15 dB/km (@633nm)

Fibres SiO2/SiO2:Ge (Corning)
– 4 dB/km loss (Junho, 1972)
– Spectral measurements forecast < 2dB/km ~800+ nm
D.B. Keck, R.D. Maurer & P.C. Schultz, “On the ultimate limit of attenuation in glass optical waveguides”, Appl.
Phys. Letters 22(7), 307-309, 1973
41
Contemporaneous History

IEE Centenary
– Colour digital TV transmission through fibre optics

Initial optical communication systems
– Graded index fibres ~840nm (AT&T)

Return to singlemode fibres
–
–
–
–
–
–
Zero dispersion @ 1300nm
Lower losses
Minimum loss @ 1550 nm
Dry fibres
30-50 km span link between repeaters
Submarine systems (TAT 1 – 1988)
42
Evolution
43
Submarine optical cables
420,000 km of fiber deployed on 100 undersea optical fiber systems
44
What we would lost

Frequent high quality long distance calls
 Mobile telephony
 High quality TV & distributed services
 Internet, Web
 YouTube !
45
Bandwidth ?
46
Power Consumption ?
47
The Future ?
“If optical fibers and semiconductor lasers were proposed
today, we would use (POTS) services on cooper pairs
forever.”
Tyinge Ly, 2002
“I cannot think of anything that can replace fiber optics.
In the next 1000 years, I cannot think of a better
system.
But don’t believe what I say, because I didn’t believe
what experts said either.”
Charles K. Kao, interview to the Radio Television Hong
Kong, 2009
48
C.K. Kao Nobel Lecture
Grazie per la vostra attenzione !