institute of photonics and electronics v.v.i. ( ... · optical fiber nobelprize 2009 charles k. kao...
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Institute of Photonics and Electronics v.v.i. (www.ufe.cz)
Technology of Optical Fibers
FILANO team
www.ufe.cz/dpt240, www.ufe.cz/~kasik
Ústav fotoniky a elektroniky AV ČR, v.v.i.
VŠCHT – ÚSK, 2013
ZÁKLADNÍ VÝZKUM:fotonika - vláknové lasery a zesilovače, optická vlákna
- optické biosenzory- státní etalon času, detekce pole živých buněk
100 FTE
Prof. Jiří HomolaČeská hlava 2009
Outline
Intro Optical fibers
TechnologiesPreform preparation – MCVD & otherssilica properties – MCVD vers. conventionalfiber drawing
Application Telecommunications, fiber lasers,amplifiers, sensors
SummaryLABO MCVD, fiber drawing, sol-gel,
magnetron sputtering
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Optical fiber
Nobel prize2009
Charles K. Kao high-purity materialsmax impurities acceptable
in ppb (10-9)
ULTRA-PURE TECHNOLOGIES
attenuation, dispersion
Optical losses in optical fibers
- trasparency of 3 mm of window-glass≈ 2 km of optical fiber
Optical fiber : dielectric structure, L<< r, ncore > nclad
[W. Snell +1626, J. Tyndall +1893]
[Ch.Kao, 1964]
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Purity of material
1. Per Analysis – PA (99 - 99,5 %)
2. Semiconductor – PP (99,9995 %)
3. Ultra-pure - FO Optipur / for trace analysis [ppb]
% – 10-2
ppm – 10-6 (parts per million)
ppb – 10-9 (parts per billion) : content of impurities acceptable in FO Optipur materials
Ultra-pure technologies - CVD !VŠCHT – ÚSK, 2013
Optical fiber preparation
MCVD
2. Fiber drawing
1. Preform
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Ultra-pure technologiesCVD - Chemical Vapor Deposition
A (g) + B(g) = AB (s)
Coldsourcegases
Reactants
Gaseousproduct
Heatflux
Substrate
Reaction zone
Goal : starting materials (g) or (l) can be purified (E.g. distilled)
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Preform preparation
MCVD – (Modified) Chemical Vapor Deposition1. Deposition of layers
1700°C
O +2
Substrate tube
Glassy layers
SiCl4
2100°C
2. Collapse
GAS MIXTURE GLASS - PREFORM
SiO2destilled
� Sequential sintering of thin glassy layers (of thickness 1-20 μm) onto inner wall of silica substrate resulting in bulk material –preform [S. R. Nagel, 1982]
� high purity (~ 101 ppb) high preciseness (better than 1 %)VŠCHT – ÚSK, 2013
MCVD process model
1. Vaporization of starting materials� VXCl4 = VOx * Po
XCl4 / (P - PoXCl4 ) … boiling point SiCl4=56°C
2. Oxidation� 1st -order kinetics, t = 0.02 s
� Chemical equilibrium :
� SiCl4 (g) + O2 � SiO2 (s) + 2Cl2
conversion ~ 0.95 – 0.99 (1500 °C)
� GeCl4 (g) + O2 � GeO2 (s) + 2Cl2
conversion ~0.5 – 0.6 (1600 °C), f(t, xSiCl4/x GeCl4)
3. Deposition� Thermophoretic efficiency
E = K . (1 – Tcool surface / T reaction) ~ 0.6
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MCVD process model
Temperature field during deposition
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MCVD process model
Process parameters :Variable :- flow rates (Si, Ge, P, B, F, Ox …)- deposition temperatureAdjustable :- temperature of starting materials (liquids)- burner speed- pressure- rotation speed of the substrate tube- substrate tube dimensions
[McChesney and Nagel, 1982, Wood, 1987, Kirchhof, 1986]
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MCVD output parameters
Microphoto of cross section of preform
Tomography of the refractive-index profile of preform
� High purity material due to FO-Optipur purity starting materials.
� High quenching rate ranging from 102 to 103 °C/s !
Concentration profile
-0,4 -0,2 0,0 0,2 0,4
0,0
0,5
6
8
10
12
14
16
Yb3+
AVG= 1570 ppm
Dop
ant
con
ce
ntr
atio
n [
mo
l%]
AL2O
3
P2O
5
Yb3+
Preform radius [mm]
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MCVD - doping of silica
0 5 10 15 20 25 30 35 40 45
1.45
1.46
1.47
1.48
1.49
1.50
1.51 SnO
PbO
Sb2O
3
F
B2O
3
P2O
5
GeO2
Al2O
3
TiO2
ZrO2
Re
fra
ctive
in
de
x (
63
3nm
, 2
0°C
)
Dopant content [mole %]
[A.B. Chynoweth, 1979, M. Shimizu, 1986, Y. Ohmori, 1983, S. H. Wemple, 1973,H. Wehr 1986, I. Kasik, 2005, K. Sanada, 1980, M. M. Karim 1994]
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Other CVD technologies (ultra-pure)
OVD
VAD
MFC
H /O
fuel2 2
Sootpreform
SiCl
+dopants4
H /O fuel2 2
SiCl
+dopants4
FLAME
Sintering
Sintering
Preform
Preform
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Other technologies : sol-gel
No melting, disorder imprinted.
O
Cl
He
2
2
SinteringDryingHydrolysiswet gelling
[J. McKenzie (US), J. B. McChesney, 1997, A. Pope (US), 1993, M. Guglielmi (It), J. Livage (F), R. Almeida (P), S. Ribeiro (Br), B. McCraith (Ir), J. Brinker (US), S.Sakka (J), V. Matejec & J.Mrazek (CZ)]
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ComparisonCVD (Chemical) x PVD (Physical)
MCVD DC magnetron sputtering
OVD etc. vacuum evaporation etc.
Layer thickness1 – 101 µm 1 - 101 nm
(however, both are reported as “thin layers”)
Deposition rateHIGH LOW
ProductsLayers, bulks Layers only
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Comparison(M)CVD x conventional
Starting materialsgaseous (g) or liquid (l) (s) solid state
melting point of oxides different melting point comparable
Purification methodsdistillation recrystallisation, remelting
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Comparison(M)CVD x conventional
ProcessDeposition of layers Melting
= oxidation+deposition+sintering
(NO MELTING)
Collapsing of preform (MELTING) Forming
- Annealing
Structure of productsGraded - profiles Homogeneous
Material purityppb (10–9, i.e. 10 –7 mol%) 10–3 mol% (99,999%)
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Properties(M)CVD x conventional
Glassforming region
Quenching rate
~ 102 - 103 °C/s ~10 °C/min
[O. V. Mazurin, 1980, J. E. Shelby, 1992]
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Properties(M)CVD x conventional
Viscosity curves
Short Long
Annealing ~ 1120-1180 °C [www.Heraeus, M. B. Volf, 1987, A. B. Chynoweth, 1979, M. Ohashi, 1992, O. V. Mazurin, 1980, K. Shiraki, 1993]
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
4
5
6
7
8
9
10
11
12
13
14
Al2O
3 (3.5%) - SiO
2
F (0.56%) - SiO2
B2O
3
P2O
5
soda-lime-silica
GeO2
Vycor
B2O
3- SiO
2
SiO2
(Tg)
(Ts)
log
(vis
co
sity [
dP
a.s
])
Temperature-1 x10
4 [K
-1]
2000 1800 1600 1400 1200 1000 800 600 400 200
Temperature [°C]
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Properties(M)CVD x conventional
Expansion coefficient KLTR 0.5 .10-6 K-1 < 3.3 x 10-6 K-1
[A. B. Chynoweth, 1979, O. V. Mazurin, 1980, S. H. Wemple, 1973]
0 2 4 6 8 10 12 14
0
5
10
15
20
SiO2-TiO
2
SiO2-B
2O
3 ∼∼∼∼ SiO
2-GeO
2
SiO2-P
2O
5
Lin
ea
r e
xp
an
sio
n c
oe
ffic
ient
x10
6 [
K-1]
Dopant content [mol%]
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Properties(M)CVD x conventional
Optical properties - transparency
Dependence of absorption at UV on technology of silica production [Safibra, 2010 & M. B. Volf, 1987]
200 300 400 500 600 700 1000 2000 3000 4000
0
20
40
60
80
100Absorption of impurities
Thickness 1 cm
VIS
Suprasil 300
Infrasil
Optical glass BK 7
Window glass
Tra
nsm
issio
n (
%)
Wavelength (nm)
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Properties(M)CVD x conventional
Optical properties – refractive index
n 633 nm, 20 °C = 1.457
n 10.6 µm, 20°C < 1 [www.heraeus.de]
1.48 < n < 1.95
[www.schott.com]
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Comparison : GLASS(M)CVD x conventional
GLASS : solid state material, amorphous, usually produced by quenching of melt, in glassy state (stable below Tg) [Hlaváč, 1981]
Structureamorphous amorphous
short-distance order (< 1 nm) longer-distance disorder (>1 nm)no X-ray crystallographic signal
nano-structure imprint feasible (glass/glassceramics)
Production - kineticssintering + melting +melting & quenching ~102 -103 °C/s quenching ~10°C/min
[G. Tammann, 1933]VŠCHT – ÚSK, 2013
Comparison : GLASS(M)CVD x conventional
Thermodynamics
Glassy state : stable bellow Tg(depending on quenching rate)
• extremely high quenching
• stable
• ? Reproducibility
• higher porosity
• lower density
Glass
Crystal
Temperature
Volu
me
Meltingpoint
Surfusion
Fast annealing
Slow annealing
Liquid
Transformationarea
Tg
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Drawing of optical fibers
� diameter
80-1000 µm
� temperature 1800-2000°C
� No thermo-insulation
� No textile
� No nanofibers !
T ~ 1400°C
Φ µ about 10 m
Die
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Comparison of fibersoptical x soft-glass
SILICA (doped with GeO2, P2O5, B2O3 …)
High productivity (relative)
• Purity FO Optipur grade
• Chemical durability
• Precise geometry (<0.5 µm)
• Low optical loss ~ 0.2 dB/km
• Strength ~ 5 GPa due to coating
• Use in OPTICS
� (CaO, MgO)-Al2O3-B2O3- SiO2
� Na2O - CaO - (Al2O3) - SiO2
� High productivity – low processing temperature, cheap starting materials
� Thermo-insulating properties
� Chemical durability
� A geometry allowing weaving
� Strength ~ 2.5 GPa (without coating, temporary)
� Use as insulators and textiles
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ApplicationApplication
Telecommunicationfibers(cables)
Fiber lasers &lifiers
Telecom amplification,
raw power …
Fiber sensorsEnvironmental,
biology,medicine…
Special fibers
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Telecommunications
Testing of 200 km telecom line
GI - technology transfer VÚSU Teplice, Hesfibel TR
SM 1300, 1550 nm
1981 – 1st demonstration of CZ optical fiber – UFE/URE/JLS
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VŠCHT – ÚSK, 2013
Telecommunications : fiber lasers and amplifiers
detectoramplifiersource
Pump source
100 km
fiber
Fiber laser
High power fiber lasers
Welding, cutting < 2kWsavings, fast processPALS
Intensity of lightSun 63 MW/m21W-fiber laser 12.7 GW/m2
Er- fiber laser, pulsed 197 fs,5m resonatorLiekki
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Fiber-optic sensors
Source
Detector
Ø 18 µm
Small devices capable of continuous and reversible monitoring of (bio)chemical species and their concentration
Principle : change of properties of the light due to chemical (physical) changes of medium.
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SUMMARY
MCVD
Suitable for the preparation of :
� silica-based materials, doped (up to 50 mol%)
� few-component (up to ~ 6 components) materials
� materials for photonics, optics, optoelectronics
� materials of high-level purity (~ 101 ppb)
� products requiring high preciseness of geometry (better 1 %)
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SUMMARYSUMMARY
1. OF technology : preparation of structures of high preciseness from materials of ultra-high purity (impurities in ppbs only).
2. OF preparation in two steps : preform preparation and fiber drawing.
(M)CVD technique (preform) makes possible to prepare multilayered tailored structures of suitable level of purity.
3. Fibers conventional (passive) and specialty (active).
4. Research of optical fibers (CR) :
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References
� J. M. Senior : Optical fiber communications - Principle and practise, Pearson Education Limited, Harlow, England, 2009.
� A. Mendez, F.T. Morse : Specialty optical fibers handbook,
Elsevier Science & Technol, USA, 2006.
� J. Schrofel, K. Novotný : Optické vlnovody, SNTL, 1986 � Saaleh, Fotonika (1 - 4), Matfyzpres� S. R. Nagel, J. B. McChesney, K. L. Walker : An overview of the
MCVD process and performance, IEEE J. Quantum Electron. QE-18 (1982) 459-477
� Československý časopis pro fyziku 1/2010, 4-5/2010, 1/2011� Jemná mechanika a optika 55 (2010)� Sdělovací technika 3/2011
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Uplatnění v oboru
UCHP - Oddělení aerosolových a laserových studií : Laserová ablační přípravananostrukturovaných prášků, RNDr. Vladislav Dřínek, CSc., PROJEKT MAGISTERSKÉHO/BAKALÁŘKÉHO STUDIA
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ALMA - Akademická laboratoř materiálového průzkumu malířských děl , RNDr. Janka Hradilová
VŠCHT – ÚSK, 2013