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Crystal Fiber based Broadband Light Sources
Sheng-Lung Huang
Institute of Photonics and OptoelectronicsNational Taiwan University
5/14/2014@Abbe School of Photonics
Outline
• Introduction to crystalline fiber (CF)
• CF based laser and nonlinear optics
• CF based optical amplifier- From highly multimode toward single mode- From glass clad to ceramic/crystal clad
• Summary
Silica fibers work so well,why bother makes them crystalline?
Let’s compare bulk crystal and crystal fiber first.
Yes, photonics crystal fibers are fascinating,it is so versatile…..
Sorry, today is about electronic crystal fiber……
4
Bulk Crystal vs. Crystal Fiber
Laser host Effective heat removal (10 x better),Less material consumption (100 x less)
Nonlinear optics Long interaction length,Tight beam confinement
Energy delivery/ high temp. sensing
Ultrahigh strength,Resistance to chemical attack
New material development
High growth rate,Uniform axial distribution
Now, silica fibers work so well,why bother makes them crystalline?
Yes, you are right, not many chances, but…
6
Why Crystalline Fiber ?
Laser host Effective heat removal (10 x better),Less material consumption (100 x less),Crystal field (for transition metal ions)
Nonlinear optics Long interaction length,Tight beam confinementHigh nonlinear coeff.
Energy delivery/ high temp. sensing
Ultrahigh strength,Resistance to chemical attack
New material development
High growth rate,Uniform axial distribution
7
Transition Metal Ion Cr4+ Doped YAG Energy Level Diagram
Td symmetry
Cr4+:YAG energy level diagram
D2d symmetry
Tanabe-Sugano diagramFor tetrahedrally coordinatedCr4+:YAG.
Dq/B=1.78 for Cr4+:YAG
d2 configuration in octahedral coordination
CFSE=160.5 kJ/mol
CFSE=106.8 kJ/mol
8
Why CFs are effective togenerate broadband emissions?
Garnet structure
(SiO4)4-(Si2O7)6-
(Si2O5)2-(Si4O11)6-
(Si6O18)12-
(Si2O6)4-
(SiO2)0
Nesosilicates Sorosilicates
Phyllosilicates Tectosilicates
Cyclosilicates
Inosilicates(single chain)
Inosilicates(double chain)
Various tetrahedron in silicates/silica
Sapphire structure
Broadband Light Source Applications
OCT report, 2010
Therapeutic window: 600-1300 nm
- High-brightness emission- Tunable laserOCT
- High-brightness emission- Tunable laser- Amplifier
Optical comm. window: 1300-1600 nm
10
Historical Overview on Crystal Fiber
Red: threat Blue: chance
Year Milestone Remark1975 Crystal fiber growth invented by Bell Lab. Burrus and Stone, US patent 4,040,890
1981 LHPG at Stanford Byer and Fejer, US patent 4,421,721
1982 Corning achieved low-loss propagation in silica Crystal fiber’s future doomed?1987 Ion implantation, diffusion cladding NTT
1991 Cr:YAG developed Bulk form
1992 Key OCT patent filedSwanson, Huang, Fujimoto, et al,US patent 5,321,501
1996 Our group started LHPG @ NSYSU Nd:YAG
1998 Lucent (formerly Bell Lab.) invented water-free fiber Broadband gain medium is needed1998 NTT developed E-gun deposited cladding on Cr:YAG Large core
1998 Our group started Cr:YAG crystal fiber For fiber amplifier
2004 Co-drawing glass-cladding invented Optics Letters, 29, 439, 2004.
2005 First CDFA developed Optics Letters, 30, 129, 2005
2007 Sapphire-tube-assisted co-drawing LHPG invented Optics Express, 16, 12264, 2008.
2008 Low-threshold and efficient Cr:YAG laser demonstrated Optics Letters, 33, 2919, 2008.
11
LHPG Grown Oxides/Fluorides
Laser host Nonlinear Upconversion
Y3Al5O12YVO4YAlO3Al2O3GdVO4Mg2SiO4Y2SiO4
LiNbO3 LiTaO3Li2B4O7
LiLuF4
Y3Fe5O12
YCOBGdCOB
Magnetic
12
Crystal Fiber Applications
Crystal fiber
Broadband emission• Amp. spontaneous emission• Tunable laser• Broadband amplifier
High mechanical strength• High power laser• High temperature sensing• Nano probe tip
High nonlinearity• Second harmonic generation• CW Raman laser
200X
Moderate drawing speed• New crystal development• 3D PCF
LD array
Nd:YAG CF
PPLN CF
Laser-Heated Pedestal Growth
Symmetrically heated fiberMolten zone
Streamline and isotherm
- P. Y. Chen, et al., Journal of Applied Crystallography, 42, 553, 2009.- C. L. Chang, et al., Journal of Crystal Growth, 318, 674, 2011.
14
LHPG Grown Crystalline Fibers
Un-clad Cr:YAG crystalline fibers
0.25 mol.%
0.05 mol.%
0.5 mol.%
[111]
011_
110_
101_
T
Selected area electron diffraction
0
0.2
0.4
0.6
0.8
1
1.2
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.52 theta (deg.)
Nor
mal
ized
inte
nsity
(a.u
.) LHPG 400 micron
CZ 500 micron
X-Ray diffraction
15
Interdiffusion Process at the Core/Clad Interface
YAG[111]-Al2O3[013]
8.5 nm0.2395 nm
[311]
0.235 nm [311]
YAG[111]-Al2O3[013]
YAG[111]-Al2O3
12 nm0.229 nm [222]
YAG[111]
3 nm
0.235 nm [311]
-Al2O3[013]
YAG in fused silica capillary
- C. C. Lai, et al., Journal of Physical Chemistry C, 116, 26052, 2012.- C. C. Lai, et al., Journal of Physical Chemistry C, 115, 20289, 2011.- C. C. Lai, et al., Journal of Applied Physics, 108, 054308, 2010.
16
Glass-clad Crystalline Fiber
-Al2O3
TEM-BFI
SAED
1.15 nm
ĪĪ2
Ī0I
ĪI0
Ī2Ī
0ĪI
SAED pattern0IĪ
Cross section imageCore
Inner cladding
17
silica nano wire
light
tapered fiber
tapered fiber
Subwavelength-Diameter Silica Nanowire
sapphire taper
flame
silica wire
drawing
Nature, vol. 426, p. 816, Dec. 2003.
50-nm diameter 4-mm long
18
Sapphire-Tube-AssisitedCo-Drawing LHPG Growth System
Sapphiretube
Vacuumpump
CO2 laser
Powercontrol
Beamexpander
Growth chamber Microscope
1000:1 stepping motor
LabVIEW controlledLHPG system Growth chamber
19
Sapphire Tube Buffering
=19 m=31 m
CO2 donut beam
Sapphire tube
Fused silica tubeCr:YAG fiber
Side view
End view
=11 m
w/o sapphire tube w/ sapphire tube
=3 m=4 m
K. Y. Huang, et al., Optics Express, 16, 12264, 2008.
20
DCF Core UniformityReal-time analysis on the hot image
Adiabaticcriterion
2
)( 21 zd
d
0
5
10
15
20
0 10 20 30 40 50 60Fiber length (mm)
Cor
e di
amet
er (m
)
-0.50.00.51.01.52.02.53.03.54.0
an
-1(
/ m
) (de
g.)
1.
2. Correlation length analysis
0 10 20 30 40 50-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Tape
ring
angl
e (d
eg.)
Fiber length (mm)
w/o sapphire tube w/ sapphire tube
21
Strain Free Glass-Clad Crystal Fiber
0 20 40 60 80 100-0.15
-0.10
-0.05
0.00
0.05
0.10
Percent diameter (%)
Stra
in (%
)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
Cr 3+ fluorescence lifetim
e
0 20 40 60 80 100-0.15
-0.10
-0.05
0.00
0.05
0.10
Percent diameter (%)
Stra
in (%
)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
Cr 3+ fluorescence lifetim
e
[-211][-101]
600 650 700 750 800 8500.0
0.2
0.4
0.6
0.8
1.0
Far-field Position 1 Position 2 Position 3
Wavelength (mn)
Cr3+
fluo
rres
cenc
e in
tens
ity (a
.u.)
4T2 → 4A2transition
R line (2E→4A2: 688.2nm) R-line sidebands
Anti-stokes
19-m core
14-m core
25-m core
11m core
19-m core
14-m core
25-m core
11m core
Strain profiles
22
Periodic Table of the Elements
Cr
Rare earth
Transition metal
Ti
Ce
Example: YAG Crystal as Ion Host
Site Local symmetry Frequent dopantA Dodecahedral site Yb3+, Ce3+, Nd3+, Er3+
B Octahedral site Cr3+
C Tetrahedral site Cr4+
Garnet structure (A3B2C3O12)projection along c-axix
Host ion Y3+(D) Al3+(T) Al3+(O)Site
symmetry D2 D2d
Dopant Å 1.159 0.53 0.675
Nd3+ (D) 1.249 +7.8%
Yb3+ (D) 1.125 -2.9%
Cr3+ (O) 0.755 +11.9%
Cr4+ (O) 0.69 +2.2%
Cr4+ (T) 0.55 +3.8%
Ca2+(D) 1.26 +8.7%
Mg2+(D) 1.03 -11.1%
Mg2+(T) 0.71 +34%
Mg2+(O) 0.86 +27.4%
Ce3+ (D) 1.283 +10.7%
Sm3+ (D) 1.219 +5.2%
Doping in YAG matrix
Lattice mismatch
A
B
C
24
Fluorescence and Refractive Index Mapping
Cr3+ fluorescence image
Cr4+ fluorescence image
CoreInner cladding
Outer cladding
30m
CoreInner cladding
Outer cladding
30m Average Cr3+ Average Cr4+ Index
Core 79% 94% 1.82Inner cladding 21% 6% 1.60~1.66
25
Impact of Ion Segregation
Cr3+ fluorescence distribution Cr4+ fluorescence distribution
J. C. Chen, et al, Journal of Crystal Growth, 274, 522, 2005.
26
Active Ion Control
CO2 laser beam
Cr,Ca:YAG
Molten zone
YAG crystal
CaO layer
Cr2O3 layer
Pull
Feed
Source material
Seed
0.00
0.05
0.10
0.15
0.20
0 20 40 60 80 100
Percent diameter (%)
Cr 2
O3
conc
ent.
(wt.%
)
w/ Cr2O3 side depositionw/o Cr2O3 side deposition
Avg. Cr2O3=0.14 wt.%
Avg. Cr2O3=0.04 wt.%
0 1 2 3 4 5 6
0
1
2
3
4
5
6
0123456789
0
543
2
Abs
orpt
ion
coef
f. (c
m-1)
Cr4+ t
/Cr (
%)
Ca/Cr
w/o annealing w/ annealing at 1350oC
1
27
Defects in the DCF Core
stacking faults (#/cm2) w/o annealing w/ annealingCaO & Cr2O3 deposition 8x1015 1.1x1015
MgO, CaO & Cr2O3 deposition 3.5x1015 3.5x1015
x x x x
xxxx
x x x
xxxx
x
[111]
[111]1 nm
Raw HRTEM image Fourier filtered image
28
Cr4+:YAG Thermal Treatment
0
1E+17
2E+17
3E+17
4E+17
0 500 1000 1500Annealing temperature (oC)
Cr4+
(#/c
m3 )
0
2E+18
4E+18
6E+18
8E+18
1E+19
1.2E+19
Cr 3+ (#/cm
3)Cr4+Cr3+
0
1E+17
2E+17
3E+17
4E+17
5E+17
0 500 1000 1500Annealing temperature (oC)
Cr4+
(#/c
m3 )
01E+182E+183E+184E+185E+186E+187E+188E+189E+18
Cr 3+ (#/cm
3)
Cr4+Cr3+
N2 annealing O2 annealing
Ti:sapphire Thermal Treatment
29600 700 800 900 10000
2
4
6
8
10
Spe
ctra
l den
sity
(pW
/nm
)
Wavelength (nm)
00 hr x 10 06 hr 12 hr 18 hr 24 hr
x 10
H2(5%)/Ar
1600 ˚C furnace
150 sccm
Teflon plug
Al2O3 plug
Ti:sapphire ASE power
0 200 400 600 800 1000 12000
1
2
3
4
5
6
AS
E (m
W)
Pump (mW)
CoreGlass-clad
Ceramic-cladSingle clad Double clad
Crystalline Fiber Family
30
c-cut
a-cut
- S. C. Pei, et al., Journal of Applied Crystallography, 43, 48, 2010.- L. M. Lee, et al., Journal of the Optical Society of America B, 24, No. 8, 1909, 2007.
Crystal Fiber based Broadband Sources
00.10.20.30.40.50.60.70.80.9
11.1
0 200 400 600 800 1000 1200 1400 1600 1800
Nor
m. s
pect
ral d
ensi
ty (a
.u.)
Wavelength (nm)
Cr:YAGTi:sapphireCe:YAG Cr:forsteriteF-center:sapphire
- K. Y. Hsu, et al., IEEE Photonics Technology Letters, 24, 854, 2012.- K. Y. Hsu, et al., Journal of the Optical Society of America B, 28, 288, 2011.- Y. S. Lin, et al., IEEE Photonics Technology Letters, 22, No. 20, 1494, 2010.- K. Y. Huang, et al., IEEE/OSA Journal of Lightwave Technology, 26, 1632 2008.- C. C. Lai, et al., Optics Express, 21, 14606, 2013.
32
Broadband and High Brightness Emission
Broadbandgain medium
Diodelaser
Emission
Disk Rod Fiber
Pump power
Emitt
ed p
ower
4π collection
Pump power
Emitt
ed p
ower
Outline
• Introduction to crystalline fiber (CF)
• CF based laser and nonlinear optics
• CF based optical amplifier- From highly multimode toward single mode- From glass clad to ceramic/crystal clad
• Summary
34
Efficient Cr4+:YAG DCF Laser
Efficient CDFL for sweep source OCT
1415 1417 1419 1421 1423 1425
-70
-50
-30
-10
10
30
1420.27 nm
Spec
tral
den
sity
( dB
m/ 0
.08
nm)
Wavelength (nm)
~70 dB
1060 / 1550
coupler
Heat sinkTE cooler
818-IRPhoto detector
Cr:YAGDCF FL=10 mm
SMF LWP filter
HI 1060
Pump at1064 nm
OSA
35
Power Budget and Polarization
Quantum defect
Pump propagation
loss
Pump ESA
Pump mode mismatch
Signal propagation
loss
Signal ESA
Stimulated emission Total
25.1% 2.6% 3.9% 16.6% 1.8% 16.4% 33.6% 100%
A
B
C
YAG matrix
Lifetime Thermal Loading
36
0 100 200 300 4003.9
4.0
4.1
4.2
4.3
4.4
T: 9.1oC↑
Life
time
(s)
Pump (mW)
Bulk Crystal fiber
T: 1.7oC↑
-5 0 5 10 15 20 25e-7
e-6
e-5
e-4
e-3
e-2
e-1
e0
Nor
mal
ized
fluo
resc
ence
Time (s)
Measured Fitted
L4 L5
HWPCr4+:YAG
crystal fiber
LPF
PDL1
1064-nm LD
L2 L3
chopper
L = 4.4 cmcore = 19 μm
Fluorescence lifetime measurement Lifetime comparison
37
LHPG Grown Crystal Fiber Lasers
Active ion Local site in YAG Guiding Pth (mW) Slope
efficiency
Nd Dodecahedron Graded index 160 28.9%
YbDodecahedron Bulk 650 50.3%
--- Single clad 140 76.3%
Cr Tetrahedron Double clad 80 33.9%
1. C. C. Lai, C. P. Ke, S. K. Liu, D. Y. Jheng, D. J. Wang, M. Y. Chen, Y. S. Li, P. S. Yeh, and S. L. Huang,Opt. Lett., 36, 784, 2011.
2. C. C. Lai, K. Y. Huang, H. J. Tsai, K. Y. Hsu, S. K. Liu, C. T. Cheng, K. D. Ji, C. P. Ke, S. R. Lin, and S. L.Huang, Opt. Lett., 34, 2357, 2009.
3. C. C. Lai, H. J. Tsai, K. Y. Huang, K. Y. Hsu, Z. W. Lin, K. D. Ji, W. J. Zhuo, and S. L. Huang, Opt. Lett., 33,2919, 2008.
38
Nonlinear Crystal Fiber- LiNbO3
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.00
5
10
15
20
25
30
35
40
45
Dom
ain
pitc
h (
m)
Fundamental wavelength m)
4851
5.7271
14551
5.7271
14551
14551
SHG by 1st QPM with 16.3 m pitch
SFG by 3rd order QPM with 16.3 m pitch ( 5.43 × 3 )
3rd order SFG
1st order SFG
1st order SHG
YX
Z
16.3-m-pitch PPLNCF
Cascade SHG (1st order)+SFG (3rd order)
39
In-Situ Poling Mechanism during LHPG
Para-electricphase
Curie isothermFreezing line
LN melt
Effective poling region
Solid liquid interface
x
x)dvxf
sin(2)21
WxX
rect(E(X)e
π
Seed
-Qu+Q
-Qd
X
-Qu+ -Qd+ Q=0
- -- ---
---- Z
Y
Cross section view
Z
Electrode Electrode
Molten zone phases
40
Tunable Blue/Green Emission by SHG+SFG
1455 nmpump source 16.3 m
PPLNCF
471.3 nm 476.7 nm 479.3 nm 482.7 nm 489.3 nm
493.0 nm 498.3 nm 502.7 nm 509.0 nm 515.0 nm
Tunable Blue/Green Laser
0
2
4
6
8
10
12
50 70 90 110 130 150Internal pump power (mW)
SHG
pow
er (m
W00.20.40.60.811.21.41.61.82
SHG
+SFG
pow
er (m
W
Raman Light Source Schemes
41
IC OC
Ramancrystal
IC OC
Lasercrystal
Q switch
pump Raman
pumpRaman
pump Raman
Ramancrystal
Ramancrystal
Ramancrystal fiber
Spon. Raman generation Resonant SRS
Intracavity spon. Raman generation Intracavity and resonant SRS
42
CW Raman Crystal Fiber Laser
I18oC
I16oC
I24oC
0 100 200 300 400 500 600048
121620242832
RCFL = 4.7%DCFL = 0.1%
RCFL = 11.7%DCFL = 3.3%
RCFL = 14.3%DCFL = 5.2%
T = 16 oC T = 18 oC T = 24 oC
Lase
r out
put p
ower
(mW
)
Incident LD pump power (mW)
1384 1388 1392 1412 1414 1416 1418-70-55-40-25-10
57 dB
1384 1388 1392 1412 1414 1416 1418-70-55-40-25-10
Pin = 326 mW Pin = 343 mW Pin = 393 mW
Pin = 105 mW Pin = 222 mW Pin = 315 mW
1384 1388 1392 1412 1414 1416 1418-70-55-40-25-10
Wavelength (nm)
37 dB
56 dB
1384 1388 1392 1412 1414 1416 1418-70-55-40-25-10
Pin = 68 mW Pin = 175 mW Pin = 240 mW
Pin = 8 mW Pin = 8 mW Pin = 8 mW
Spec
tral d
ensi
ty (
dBm
/ 0.
08 n
m)
AS Raman, RCFL Raman pump, DCFL
(a)
(b)
(c)
(d)
IC OCLD
C. C. Lai, et al., Applied Physics Letters, 100, 261101, 2012.
Outline
• Introduction to crystalline fiber (CF)
• CF based laser and nonlinear optics
• CF based optical amplifier- From highly multimode toward single mode- From glass clad to ceramic/crystal clad
• Summary
44
Optical Fiber Amplifier Review
Comparison of fiber amplifiers
FluoridePDFA Fluoride
TDFA
FluorideHDFA
SilicaEDFATellurite
EDFA
Silic
a fib
er lo
ss (
dB/k
m)
0
0.2
0.4
0.6
0.8
1.0
1200 1300 1400 1500 1600 17000
10
20
30
40
Gai
n (d
B)
Wavelength (nm)
CDFA
1.2 1.3 1.4 1.5 1.6 1.71985
1990
1995
2000
2005TDFA-T
EDFA-T
EDFA-S
TDFA-S
EDFA-F
EDFA-S
EDFA-S
TDFA-F
TDFA-FPDFA-F
Year
Wavelength (m)
PDFA, TDFA, and EDFA denote Pr, Tm, and Er-doped FA.-F, -T, and -S, denote fluoride, tellurite, and silica doping.
Historical review
45
Fusion Splicing with SM Silica Fiber
0 pixels 510 pixelsElectrode
SMF
320-μm double cladding Cr:YAG fiber
Monitor area235 pixels
Before fusion After fusion
X direction
Y direction
Return loss measurement
Insertion+ prop. loss measurement
-3.4
-3.3
-3.2
-3.1
1450 1500 1550 1600 1650Wavelength (nm)
Tran
s. lo
ss (d
B)
-80-70-60-50-40-30-20-10
0
0 50 100 150 200 250 300 350 400
Position (mm)
Ret
urn
loss
(dB At face 1: -35.7 dB
Gross Gain Simulation
46
5 10 15 20 25 30 35 40 455
10
15
20
25
30
35
40
45
Length (cm)
Ggr
oss (
dB)
20 m 11 m 14 m 19 m 25 m
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80.0
0.2
0.4
0.6
0.8
1.0Ggross= 27,73 dB, when forward ratio= 0.5 and L= 0.8 m
Length (m)
Forw
ard
ratio
5.1006.8738.64710.4212.1913.9715.7417.5119.2921.0622.8324.6126.3827.80
Cr:YAG DCFCore: 20 m
CDF length dependence Dual pump ratio
Single-mode crystal fiber is required to have high gain.
47
Mode Number Reduction
CO2 laser beam
Cr,Ca:YAG
Molten zone
Cr,Ca:YAG crystal
TiO2 layer
Pull
Feed
Source material
SeedRefractive index profile
- C. N. Tsai, et al., Journal of Crystal Growth, 310, 2774, 2008.- J. C. Chen, et al., Journal of Applied Physics, 99, 093113, 2006.
Glass Cladding of CF
Material CTE(10-6/K)
Thermal conductivity
(W/m/K)
YAG 7-8 13
Sapphire 5.0-6.6 25.12
Fused silica 0.55 1.38
PYREX 3.25 1.1
Aluminosilicate8252 4.6 1.1
N-SF57 8.5 0.99
N-LaSF9 7.4 0.79
N-LaSF41 6.2 0.79
1.72
1.77
1.82
1.87
1.92
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Ref
ract
ive
inde
x
Wavelength (μm)
Sapphire o-ray
Sapphire e-ray
YAG
N-SF57
N-LaSF9
Thermal propertyDispersion
Yb3+ Cr4+ Er3+Ce3+
49
Fine Tuning of Glass Index
100 101 102 103 104 105 106 107 108-0.020
-0.015
-0.010
-0.005
0.000
0.005
Inde
x ch
ange
Annealing rate (oC/hr)
Index change
Tg-120
Time
T (C)Tg
25
60 C/Hr
14 C/Hr7 C/Hr
6 Hr
Annealing/cooling rate
End face image
1 5 0 2 0 0 2 5 0 3 0 0 3 5 01 .7 4
1 .7 6
1 .7 8
1 .8 0
1 .8 2
1 .8 4
1 .8 6N -S F 5 7c la d d in g
N -S F 5 7c la d d in g
Ref
ract
ive
inde
x
P o s it io n (m )
Y A Gc o re
Index profile
780 nm 633 nm
Measurement Simulation532 nm
Few-Mode CF by High-Index Glass Clad
0.4 0.6 0.8 1.0 1.2 1.4 1.6
1.80
1.82
1.84
1.86
1.88
Wavelength (m)
Inde
x
0.00
0.05
0.10
0.15
0.20
NA
N-SF57 bulk
YAG
N-SF57 capillary
K. Y. Hsu, et al, Optical Materials Express, 3, No. 6, 813, 2013.
Few Mode YAG-DCF Using N-LaSF9
51
YAG/N-LaSF9/BS DCF
-100 -50 0 50 1001.4
1.5
1.6
1.7
1.8
1.9
Ref
ract
ive
inde
x
Positsion (m)
Core
Inner cladding(N-LaSF9)
Outer cladding(Borosilicate)
1.79
1.80
1.80
1.81
1.81
1.82
1.82
1.83
1.83
1.0 1.2 1.4 1.6 1.8
Ref
ract
ive
inde
x
Wavelength (μm)
YAG
N-SF57
N-LaSF9
N-LaSF9 dispersion
Few-Mode CF by Ceramic Clad
Single crystalline core
High purityceramic clad
Ceramic clad
-60 -40 -20 0 20 40 600.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
Ref
ract
ive
inde
x
Position (m)
Ceramiccladding
Ceramiccladding
Core
Refractive index profile
Take home message
-- Glass-clad crystalline fibers have been developed withvarious active ions, host crystals, and cladding materialfor broadband emission,
-- Glass-clad crystalline fibers have been shown advant-ageous on biomedical tomography, tunable laser andnonlinear wavelength conversion,
-- High power and high gain utilization of crystalline fiberswith clad pumping and single mode operation are under development.
Post docs.:
Ph.D. students:
Full time engineers:
Administration: Ya-Ting Hsu
Acknowledgment
-- Crystal fiber growth: Shih-Chang Wang-- 800-nm OCT system: Tuan-Shu Ho-- 1.4-μm OCT system: Yu-Ta Wang-- Tunable laser: Dong-Yo Jheng-- Image processing: Chia-Kai Chang-- Fiber based MOPA: Chun-Lin Chang (now postdoc at MIT)-- EUV based OCT: Yen-Yin Li
-- OCT on single cell: Nai-Chia Cheng-- Crystal fiber devices: Teng-I Yang-- Software development: Chien-Chen Huang-- Crystal fiber growth: Cyun-Ling Jian
-- Novel crystal fiber growth: Kuang-Yu Hsu-- Micro/Nano spectroscopy: Chien-Chih Lai (now with NDWU)-- High power fiber laser: Yin-Wen Lee (now with NTUT)-- OCT on dermatology: Chien-Chung Tsai
Vielen Dank fürIhre Aufmerksamkeit.