1. Hypolito José KalinowskiHypolito José Kalinowski
National Institute of Photonics Science and
Technology for Optical Communications – UTFPR
Branch
The 2009 Nobel Prize for FibreThe 2009 Nobel Prize for Fibre
Optics and its OriginsOptics and its Origins

2. 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. 3
FOTONICOMFOTONICOM
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. 4
OutlineOutline
• Electromagnetic Aspects
• Materials Aspects
• Putting all together
• B.K. (Before Kao)

5. 5
2009 Nobel Prize in Physics2009 Nobel Prize in Physics
Charles Kuen KaoCharles 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. 6
Once upon a time... (?)Once upon a time... (?)

7. 7
James Clerk MaxwellJames Clerk Maxwell
The Royal Society of Edinburgh, George Street, 07 Oct 2009

8. 8
Electromagnetism before 1864Electromagnetism before 1864
JB
t
B
E
B
E
0
0
0
µ
ε
ρ
=×∇
∂
∂
−=×∇
=•∇
=•∇  Gauss Law
 Non-existing magnetic
monopoles
 Faraday’s Law
 Ampere’s Law

9. 9
Electromagnetism before 1864Electromagnetism before 1864
 Taking the divergence
 That’s OK.
 Repeating
 Correct for J constant,
but ...
 Electrodinamics, charge
conservation
 For all space!!! ???
( )
constant
0
00
0
0
=






∂
∂
−=
•∇=×∇•∇
=
∂
•∂∇
−==×∇•∇
∂
∂
−•∇=×∇•∇
ρ
ρ
µ
µ
t
JB
t
B
t
B
E

10. 10
Maxwell EquationsMaxwell Equations
t
D
JH
t
B
E
B
D
∂
∂
+=×∇
∂
∂
−=×∇
=•∇
=•∇
0
ρ
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. 11
Light as an Electromagnetic WaveLight as an Electromagnetic Wave
 Transversal oscilations
in the same E.M.
Medium.
 Velocity of propagation
 Original agreement
~ 1,4%
00
1
µε
=c
J.C. Maxwell, “On physical lines of force”, Phil. Mag., 161ff, 1861
Part III: The Theory of Molecular Vortices applied to Static Electricity
J.C. Maxwell, “A Dynamical Theory of the Electromagnetic Field ”,
Phil. Trans. Royal Soc., 155, 459ff, 1865 (8 Dec 1864)

12. 12
Helmholtz EquationHelmholtz Equation
PropagationPropagation
0),(][),(
),(),,,(
1
00
222
)(
00
2
2
02
2
00
2
=−−∇
=
=
∂
∂
−
∂
∂
−=−∇=×∇×∇
−
yxEyxE
eyxEtzyxE
c
t
P
t
E
EE
tzi
εµωβ
µε
µµε
ωβ
Used by Maxwell, “A Dynamical...”, op. cit.

13. 13
Eletromagnetism after MaxwellEletromagnetism after Maxwell
Free Space Eletromagnetism
Linear, isotropic, dispersionless medium, free
of charges or currents
Elementary solutions based on propagating
harmonic waves (superposition).

14. 14
Free Space ElectromagneticFree Space Electromagnetic
PropagationPropagation
Electromagnetic waves
Wireless telegraphy
Radio
Television
Communication satellites
Microwave links
Wireless & mobile communications

15. 15
Eletromagnetism after MaxwellEletromagnetism after Maxwell
 Eletromagnetism in material media
 Polarization (P) and Magnetization (M)
 Non linear, anisotropic, dispersive media
 Solutions based in harmonic propagating waves
(superposition ⇒ wave packets)
HHMHB
EEPED
m
e
µµχµ
εεχε
=+=+=
=+=+=
00
00
)1()(
)1(

16. 16
Dielectric WaveguidesDielectric 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. 17
Near infrared
Frequency
Wavelength
1.6
229
1.0 0.8 µm0.6 0.41.8 1.4
UV
(vacuum) 1.2
THz193 461
0.2
353
Longhaul Telecom
Regional Telecom
Local Area Networks
850 nm
1550 nm
1310 nm
CD
780 nm
HeNe Lasers
633 nm
Optical SpectrumOptical Spectrum

18. 18
Optical WaveguideOptical Waveguide

19. 19
Fibre Optics (after Kao)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. 20
Once upon a time... ( again !?)Once upon a time... ( again !?)

21. 21
Glass and its BenefitsGlass 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. 22
A World of GlassA World of Glass
A. Macfarlane & G. Martin, ScienceA. Macfarlane & G. Martin, Science 305 (5689)305 (5689), 1407, 2004, 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. 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. 24
Glass FibresGlass 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. 25
Light GuidingLight 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, 800-
802, 1842.

26. 26
Dissemination ?Dissemination ?

27. 27
Fibre ImagingFibre 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. 28
Fibre Optics – 1950’s-1960’sFibre 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. 29

30. 30
Fibre ImagingFibre Imaging
H. Hopkins & N.S. Kapany
– Gastric endoscope
– 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
H. Hopkins & N.S. Kapany,
Nature 173, 39-41, 1954
L.E.Curtiss, Glass fibers optical devices, US
Patent 3589793, dep. 1957, conc. 1971.
B. Hirschowitz, Gastroenterology 35, 50-53,
1958

31. 31
Curtiss’ ProcessCurtiss’ Process
 Curtiss introduced the
preforma concept
– Concentric rods of high/low
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)
High n Low n

32. 32
Fibre Optics before KaoFibre 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. 33
Lasers (1958-1966)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. 34
Fibre Optics for CommunicationsFibre 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
α < 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. 35
Kao & HockhamKao & Hockham

36. 36
• Literature review
• Analysis of properties, several
materials
• Methodology
• Theory
• Experiments
• Model comparison
• Results & Discussion
• Proposition & Conclusions
LP01
LP11
LP21
LP12
TE02, TM02
HE12 + EH11
EH + HE

37. 37
Conclusions – Kao & HockhamConclusions – Kao & Hockham
– Practical optical guide,
Φ ∼100 λo
– 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. 38
Fibres just afterFibres 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. 39
Ultra pure Glass Fibre OpticsUltra pure Glass Fibre Optics
Loss measurements in optical glasses ( l ~ 30
cm)
– Differential spectrometry ( ∆l = 20 cm)
Fused silica losses
– (< 1ppm impurities)
– < 5 dB/km
M.W. Jones & K.C. Kao (1969), “Spectrophotometric studies of ultra low loss
optical glasses 2:double beam method", J. Sci. Instrum.: 331-335
K.C. Kao & T.W. Davies (1968), “Spectrophotometric studies of ultra low loss
optical glasses 1:single beam method", J. Sci. Instrum.: 331-335
⇒ Possible to purify optical glasses to obtain required loss !

40. 40
6 years conquist6 years conquist
 Glass purifying
 Double crucilble process (already used in past)
– Dyot (sugar molasses optimization)
 Flame photolysis (Corning)
– Fibre SiO2/SiO2:Ti
– 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
F.P. Kapron, D.B. Keck & R.D. Maurer, “Radiation losses in glass
optical waveguides”, Appl. Phys. Letters 17, 423-425, 1970

41. 41
Contemporaneous HistoryContemporaneous 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. 42
EvolutionEvolution

43. 43
Submarine optical cablesSubmarine optical cables
420,000 km of fiber deployed on 100 undersea optical fiber systems

44. 44
What we would lostWhat we would lost
Frequent high quality long distance calls
Mobile telephony
High quality TV & distributed services
Internet, Web
YouTube !

45. 45
Bandwidth ?Bandwidth ?

46. 46
Power Consumption ?Power Consumption ?

47. 47
The Future ?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. 48
Grazie per la vostra attenzione !
C.K. Kao Nobel Lecture