self-mode-locking investigation of high-power optically pumped semiconductor laser advisor: yung fu...
TRANSCRIPT
Self-Mode-Locking Investigation of High-Power Optically Pumped Semiconductor Laser
Advisor: Yung Fu Chen
Student: Yi Chun Lee
Date: 2010/07/09
Solid-State Laser Physics Lab.
NCTU Electrophysics
Y.C. Lee
高功率光激發式半導體雷射之自鎖模研究
Outline1. Introduction 1.1 Background and Motivation
1.2 OPSL V.S DPSSL
1.3 OPSL Technology
2. OPSL Experimental Results 2.1 OPSL Parameter Optimized
2.2 Spontaneous Mode-Locking of OPSL
2.3 Theoretical Simulation
3. Summary and Future Work
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
• Flashlamp Pumped Double Frequency Nd:YAG Laser ~532nm
• Flashlamp Pumped Nd:YAG Laser ~1064nm
• Diode Pumped Double Frequency Nd:YVO4 Laser ~532nm
• Diode Pumped Double Frequency Nd:YAG Laser ~561nm
• Optical Pumped Semiconductor Laser ~577nm
• Diode Laser ~810nm
閉角型青光眼之小梁成型術
視網膜剝離、眼底止血
青光眼治療、眼底光凝結手術
白內障手術眼底黃斑部病變
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Applications for OPSL
• Medical Field• Life Science and Research• Forensics• Graphic Arts and Display
Optically Pumped Semiconductor Laser
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
60fs
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Polarizer
Cr4+
Crystal
Output Coupler
Flash Lamp
1064 nm
Reflector Mirror
Reflector
Reflector
Nd:YAG Rod
2 ns/div
Flash lamp pumped passively Q-switched Nd:YAG laser
Strange Phenomenon in Time DomainStrange Phenomenon in Time DomainNCTU
Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Tr
Fiber-coupled LD @976 nm
HR @ 1030~1100 nm
FP filter
HT@976 nmHR@1030~1100 nm
Laser output
Yb doped double-clad fiber PM; clad/core: Dia. 250/30 μm (3m) NA >0.46 /<0.06
cavity
R~4%
3x50 QWs
Diode pumped passively Q-switched Yb-doped fiber laser
10 ns/div
Strange Phenomenon in Time DomainStrange Phenomenon in Time DomainNCTU
Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Tr
100 ns/div 1 ns/div 2 ns/divTr Tr
Cw-pumped diffusion-bonded Nd:YVO4 laser
Cavity length : 19 cm
Cavity length : 45 cm
Nd:YVO4 Crystal
Output Coupler
Coupling Lens
Diode Pumped Diffusion-Bonded Nd:YVO4 LaserDiode Pumped Diffusion-Bonded Nd:YVO4 Laser808nm Laser Diode
Strange Phenomenon in Time DomainStrange Phenomenon in Time DomainNCTU
Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
1064nm
Self-Mode-Locked Nd:YVO4 Laser Self-Mode-Locked Nd:YVO4 Laser
200 ps/div
Stable CW mode locking and short pulse width
Wavelength (nm)
1064.2 1064.3 1064.4 1064.5 1064.6
Inte
nsit
y (a
.u.)
0
2
4
6
8
10
12
Delay time (ps)
0 20 40 60 80 100 120 140
Inte
nsity
(a.
u.)
0
50
100
150
200
500 ns/div(a)
(b) 500 ps/div
(c) pulse width ~ 23 ps
39 ps
(d)
Wavelength (nm)
1064.2 1064.3 1064.4 1064.5 1064.6
Inte
nsit
y (a
.u.)
0
2
4
6
8
10
12
Delay time (ps)
0 20 40 60 80 100 120 140
Inte
nsity
(a.
u.)
0
50
100
150
200
500 ns/div(a) 500 ns/div(a)
(b) 500 ps/div(b) 500 ps/div
(c) pulse width ~ 23 ps
39 ps
(d)
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Output coupler
Fiber coupled LD
DPSSL – Diode Pumped Solid State Laser 二極體激發式固態雷射 OPSL – Optically Pumped Semiconductor Laser 光激發式半導體雷射
In 1980s, the progress in the growth technology of semiconductor
heterostructures developed the high-power diode laser pumped
with a solid gain medium is so called diode-pumped solid-state
(DPSS) lasers.
In 1997, M. Kuznetsov, F.Hakimi and A. Mooradian demonstrated
the first optically-pumped semiconductor laser (OPSL).
OPSL V.S DPSSL
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
△Ec
△Ev
Eg Eg well
barrier
The Mechanism of Stimulated Emission - Four-Level System in Solid-State Laser and Semiconductor Laser
OPSL V.S DPSSL
NCTU Electrophysics
Solid-State Laser Physics Lab.
Y.C. Lee
OPSL
Optically Pumped Semiconductor Laser
Diode Pumped Solid State Laser
DPSSLV.S
OPSL V.S DPSSL
NCTU Electrophysics
Solid-State Laser Physics Lab.
Y.C. Lee
• Semiconductor as Gain Medium - Substrate - Quantum Well - Bragg Mirror
OPSL Technology
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
GaAs substrate based
InP substrate based
AlGaAs (800-870nm)
InGaAs (870-1150nm)
GaInNAs (1.1-1.5μm)
Wavelength > 1.3μm
OPSL Technology
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
SubstrateMulti-layer mirrors (DBRs)
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
Laser optical standing wave
Surface barrier
Cap layer
Pumping absorbing region
λ /2
Quantum wells
Ene
rgy
Semiconductor air
SubstrateMulti-layer mirrors (DBRs)
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
Laser optical standing wave
Surface barrier
Cap layer
Pumping absorbing region
λ /2
Quantum wells
Ene
rgy
Semiconductor air
Fig4.1.2 Bandgap diagram and operation principle of the OP-VECSEL
SubstrateMulti-layer mirrors (DBRs)
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
Laser optical standing wave
Surface barrier
Cap layer
Pumping absorbing region
λ /2
Quantum wells
Ene
rgy
Semiconductor air
SubstrateMulti-layer mirrors (DBRs)
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
1 0 1 2 3 4 5 6 7 8 9 100.5
1
1.5
2
2.52.5
0.5
1 sin x( ) 2
101 x
Laser optical standing wave
Surface barrier
Cap layer
Pumping absorbing region
λ /2
Quantum wells
Ene
rgy
Semiconductor air
Fig4.1.2 Bandgap diagram and operation principle of the OP-VECSEL
Substrate
Active region
Cap layer
x
…..
…..
30 periods
2
• The Length of Quantum Well would be designed as 1/2 laser wavelength
• Laser Wavelength would slightly shifted according to quantum well design.
OPSL Technology
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Outline1. Introduction 1.1 Background and Motivation
1.2 OPSL V.S DPSSL
1.3 OPSL Technology
2. OPSL Experimental Results 2.1 OPSL Parameter Optimized
2.2 Spontaneous Mode-Locking of OPSL
2.3 Theoretical Simulation
3. Summary and Future Work
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Cavity Length
NCTU Electrophysics
Solid-State Laser Physics Lab.
OPSL Optimized
Pumping Source
Semiconductor Gain Medium
Y.C. Lee
1060 nm
OPSL Optimized
OPSL Optimized by using
• Different Radius of Output Coupler
• Cavity Length
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Focusing lens
Semiconductor Gain Medium Output
Coupler
Laser Diode
1060 nm
High speed photo-detector
Pumped Current (A)
10 15 20 25 30
Ave
rage
Out
put P
ower
(W
)
0
2
4
6
8
Cavity Length 30mm
Cavity Length 50mm
Pumped Current (A)
12 14 16 18 20 22 24 26 28 30
Ave
rage
Out
put P
ower
(W
)
0
2
4
6
8
10
Cavity Length 25 mmCavity Length 50 mmCavity Length 100 mm
Pumped Current (A)
12 14 16 18 20 22 24 26 28 30
Ave
rage
Out
put P
ower
(W
)
0
2
4
6
8
Cavity Length 50 mmCavity Length 25 mm
ROC = 50mmCavity Length = 30mm, Max Power ~7.4WCavity Length ~ 50mm, Max Power ~7.03W
ROC = 250mmCavity Length = 25mm, Max Power ~7.8WCavity Length = 50mm, Max Power ~8.0WCavity Length = 100mm, Max Power ~ 7.8WROC = 2000mm
Cavity Length = 25mm, Max Power ~6.8WCavity Length = 50mm, Max Power ~6.7W
ROC = 250mmCavity Length = 50mm, Max Power ~8.0W
• Different Radius of OC and Cavity Length.OPSL Optimized
NCTU Electrophysics
Solid-State Laser Physics Lab.
Spontaneous Mode-Locking of OPSL
Mode-Lock Optimized
5ns/div
Power Optimized
5ns/div
NCTU Electrophysics
Focusing lens
Semiconductor Gain Medium Output
Coupler
Laser Diode
1060 nm
Digital oscilloscope
High speed photo-detector
Spontaneous Mode-Locking of OPSL
Pump power (W)
4 6 8 10 12 14 16 18 20 22
Ave
rage
Out
put P
ower
(W
)
0
2
4
6
8
IP Curve of Mode Locking for 25cm Cavity LengthIP Curve of Power Optimized for 25cm Cavity Length
Wavelength (nm)
1058 1059 1060 1061 1062 1063 1064
Inte
nsit
y (a
.u.)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Specturm of Mode-Locking Spectrum of Power Optimized
ROC = 250mmCavity Length ~ 250mm
NCTU Electrophysics
5ns/div5ns/div
Power Optimized Mode-Lock Optimized
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length ~ 250mm
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 187mm
Pump power (W)
4 6 8 10 12 14 16 18 20 22
Ave
rage
Out
put P
ower
(W
)
0
2
4
6
8
IP Curve of Mode Lock Optimized for 18.75cm(3:1) Cavity LengthIP Curve of PowerOptimized for 18.75cm(3:1) Cavity Length
Wavelength (nm)
1058 1059 1060 1061 1062 1063 1064
Inte
nsity
(a.
u.)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Specturm of Mode-Locking Spectrum of Power Optimized
NCTU Electrophysics
5ns/div5ns/div
Power Optimized Mode-Lock Optimized
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 187mm
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Spontaneous Mode-Locking of OPSL
Pump Power (W)
4 6 8 10 12 14 16 18 20 22
Ave
rage
Out
put P
ower
(W
)
0
1
2
3
4
5
6
7
IP Curve of Mode Lock Optimized for 12.5cm(4:1) Cavity LengthIP Curve of Power Optimized for 12.5cm(4:1) Cavity Length
ROC = 250mmCavity Length = 125mm
Wavelength (nm)
1058 1059 1060 1061 1062 1063 1064
Inte
nsit
y (a
.u.)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Spectrum of Mode-Locking Spectrum of Power Optimized
NCTU Electrophysics
2ns/div
Power Optimized Mode-Lock Optimized
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 125mm
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
2ns/div
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 86mm
Pump power (W)
4 6 8 10 12 14 16 18 20 22
Ave
rage
Out
put P
ower
(W
)
0
1
2
3
4
5
6
7
IP Curve of Mode Lock Optimized for 8.6cm(5:1) Cavity LengthIP Curve of Power Optimized for 8.6cm(5:1) Cavity Length
Wavelength (nm)
1058 1059 1060 1061 1062 1063 1064
Inte
nsity
(a.
u.)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Specturm of Mode-Locking Spectrum of Power Optimized
NCTU Electrophysics
2ns/div2ns/div
Power Optimized Mode-Lock Optimized
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 86mm
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Pump Power (W)
4 6 8 10 12 14 16 18 20 22
Ave
rage
Out
put P
ower
(W
)
0
1
2
3
4
5
6
7Mode Lock Optimized for 12.5cm(4:1) Cavity LengthPower Optimized for 12.5cm(4:1) Cavity LengthFundamental Mode for 12.5cm(4:1) Cavity Length
Spontaneous Mode-Locking of OPSL
ROC = 250mmCavity Length = 125mm
NCTU Electrophysics
Power Optimized
2ns/div
2ns/div
Mode-Lock Optimized
2ns/div
Fundamental Mode
Solid-State Laser Physics Lab.
Spontaneous Mode-Locking of OPSL
• Scan the Beating to determine the distribution of high-order mode.
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Focusing lens
Semiconductor Gain Medium Output
Coupler
Laser Diode
1060 nm
Digital oscilloscope
High speed photo-detector
1 2 3 4 5 6 7
8
9
10
11
2ns/div1
2ns/div8
2ns/div4
2ns/div7
2ns/div62ns/div11
2ns/div3
Y.C. Lee
1.6 3.2 4.8. 6.4. 8.0.
-75
-35
-45
-55
-65
Frequency (GHz)
Spec
tral
pow
er d
ensi
ty
(dB
m)
Spontaneous Mode-Locking of OPSL
Longitudinal Frequency
Transverse Frequency
11 21
TR
cos g gf
T
1ii
Lg
R
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Fundamental Mode
High-Order Mode
1 4 7
8
11
Detected Point
3 6
High-Order Mode
Spontaneous Mode-Locking of OPSL
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
R
lnmqq
lck cav
cav
nmqnmq 1cos
1)( 1
0,,
,,
q 0 表示縱向模態的指標, lcav 代表有效的共振腔長, R 為曲率半徑。
Rnmq
nmq z
znmi
ctzikzR
yxik
nmz
yx
nmnmq eeez
yH
z
xHe
znmtzyxE
1
,,
22
,,2
22
tan)1()()(2
)(
)(
)(
0,, )(
2
)(
2
)(! !2
1),,,(
1
0,,, ),,,(),,,(
M
qnmq
Mnm tzyxEtzyxE
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Theoretical Simulation
NCTU Electrophysics
Solid-State Laser Physics Lab.
),,,(10
3),,,(
2
1),,,(),,,( 0,11,00,0, tzyxEtzyxEtzyxEtzyxE MMMM
nm
Y.C. Lee
Theoretical Simulation
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Theoretical Simulation
2ns/div1
2ns/div3 3 2ns/div
2ns/div1
2ns/div22 2ns/div
NCTU Electrophysics
Solid-State Laser Physics Lab.
Experimental Results Theoretical Simulation
Y.C. Lee
2ns/div7 2ns/div7
2ns/div62ns/div6
5 2ns/div
NCTU Electrophysics
Solid-State Laser Physics Lab.
2ns/div4 2ns/div4
Y.C. Lee
5 2ns/div
9 2ns/div9 2ns/div
10 2ns/div10 2ns/div
2ns/div11 11 2ns/div
NCTU Electrophysics
Solid-State Laser Physics Lab.
2ns/div8 8 2ns/div
Y.C. Lee
1 2 3 4 5 6 7
8
9
10
11
2ns/div1
2ns/div8
2ns/div4
2ns/div7
2ns/div62ns/div11
2ns/div3
2ns/div1
2ns/div73 2ns/div
11 2ns/div 2ns/div6
2ns/div4
8 2ns/div
Y.C. Lee
Outline1. Introduction 1.1 Background and Motivation
1.2 OPSL V.S DPSSL
1.3 OPSL Technology
2. OPSL Experimental Results 2.1 OPSL Parameter Optimized
2.2 Spontaneous Mode-Locking of OPSL
2.3 Theoretical Simulation
3. Summary and Future Work
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Summary
OPSL also discovered the spontaneous mode-locking phenomenon.
The beating of the mode-locking output pulse trains are observed of transverse modes coupling.
Theoretical simulation is matched to experimental results.5ns/div 5ns/div
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
0/1 1/1
1/2
2/31/3
1/4 3/42/5 3/5
1/5 2/7 3/8 3/7 4/7 5/8 5/7 4/6
1/6 2/9 3/11 3/10 4/11 5/13 5/12 4/9
NCTU Electrophysics
Solid-State Laser Physics Lab.
Farey Tree
Y.C. Lee
Future Work
1:3
NCTU Electrophysics
Solid-State Laser Physics Lab.
Future Work
Y.C. Lee
1:4
2ns/div
NCTU Electrophysics
Solid-State Laser Physics Lab.
Future Work
Y.C. Lee
2:5
NCTU Electrophysics
Solid-State Laser Physics Lab.
Future Work
Y.C. Lee
5:12
NCTU Electrophysics
Solid-State Laser Physics Lab.
Future Work
Y.C. Lee
5ns/div
7:17
12:29
NCTU Electrophysics
Solid-State Laser Physics Lab.
Future Work
Y.C. Lee
Focusing lens
Semiconductor Gain Medium Output
Coupler
Laser Diode
1060 nm
Digital oscilloscope
High speed photo-detector
SESAM
Future Work
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee
Thanks for your attention!
NCTU Electrophysics
Solid-State Laser Physics Lab. Y.C. Lee