4 laser with an intracavity periodicallypoled lithium niobate Bragg modulator K G Hong 1 S T Lin 2 M D Wei 1 Department of photonics National Cheng Kung University 1 Department of Photonics National Cheng Kung University No1 University Road Tainan City 701 ID: 804836
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Slide1
Hysteresis loop and pattern from the dual-wavelength competition in a Nd:YVO4 laser with an intracavity periodically-poled lithium niobate Bragg modulator
K. G. Hong1S. T. Lin2M. D. Wei1*
Department of photonics, National Cheng Kung University
1
Department of Photonics, National Cheng Kung University, No.1, University Road, Tainan City 701,
Taiwan.
2
Department of Photonics, Feng Chia University, 100,
Wenhwa
Road,
Seatwen
, Taichung 407,
Taiwan.
*E-mail: mdwei@mail.ncku.edu.tw
Slide2OutlineDual-wavelength laserPast study of our Lab Laser Phys. 21, 1039-1041 (2011)
T-type cavity designCavity loss modulator – EO PPLN Bragg modulator
Optical
bistability
– Hysteresis loop
Pattern formationSummary
Slide3Dual-wavelength laser
4
F
3/2
4
F
5/2
4
I
13/2
4
I
11/2
4
I
9/2
808 nm
1064 nm
1342 nm
Nd
-doped laser
Simultaneously
emit dual-wavelength:
Nd:YAlO
3
, Nd:YVO
4
, Nd:GdVO
4
,
Nd:YAG, Nd:LuVO4......et al.Energy competitive behavior: 4F3/2→4I11/2 : 1064 nm. 4F3/2→4I13/2 : 1342 nm. Consume populations on the same energy level (4F3/2) Instability. Reduce the competition 1.Adjusting cavity mode Appl. Phys. B 70, 475-478 (2000). 2.Cavity loss IEEE J. Sel. Top. Quant. Electr. 23, 605-612 (1987).Optical bistability : (1064 nm only) Resonator configuration Opt. Lett. 10, 232-234 (1985).
Yb-doped laser:Bistablilityinput–output hysteresis loop (1040nm&1537nm)Residual pump Appl. Phys. B 85, 545-548 (2006).Er-doped laser:nonlinear saturable absorption IEEE Photonic. Tech. L. 14, 1252-1254 (2002).
Slide4Continuous-Wave Simultaneous Dual-Wavelength and Power-Ratio-Tunable Operation at 1064 and 1342 nm in an Nd:LuVO4 Laser
L1064=18.05 (cm)
L
1064
=16.98 (cm)
Hsu, C. C., Wu, S. S., Chou, C. C. and Wei, M. D. Laser
Phys. 21
, 1039-1041 (2011)
T-type laser cavity:
Tuning
cavity
mode
at
1064nm
only.
Three mirror configuration.
M
ake cavity mode varies enormously.
Slide5T-type cavity Nd:YVO4: Nd-doped 0.5%, c-cut, 3*3*8mm, S
1&S2:AR@1000-1450nmPPLN: AR@1064 , QPM period(μm) 20.3/25.74M1: HT@808nm, HR@1064&1342nm, PL
OC
1: PR@1342nm, R=99%, r
c1=200 (mm) OC
2: PR@1064nm, R=90%, rc2=150 (mm)
B.S.: HT@1342nm, HR@1064nm
F
1
: 1342nm
bandpass
filter
F
2
: 1064nm
bandpass
filter
Pump spot size at Nd:YVO
4
: 400 (
μ
m)
Cooling temperature: 18 (
℃)
Cavity length:
L
1342
=116.9 (mm)
L
1064
=141.8 (mm)The EO PPLN is an cavity loss modulator.
Slide6EO PPLN Bragg modulator
Z
Y
X
10
mm
20.3
μ
m
15
mm
2
mm
θ
B
θ
B
m=0
m=1
Bragg condition:
2Λsinθ
B
,
m
=
mλ
0
/n
m is diffraction order.
Λ=20.3
μ
m.
For m=1 at 1064 nm ,
θ
B
=0.7
∘
x
y
z
Slide7Intracavity Transmission The transmission of EO PPLN versus drive voltage at
m = 0.The half-wave voltage of EO PPLN is about 507.9 V
Slide8Output slope efficiencyCavity length: (T-type cavity)L1064=141.8 (mm) L
1342=116.9 (mm), the strongest position of extracting energySingle emission lights(intracavity transmission T=89.05%)
Threshold
Pth,1064
= 3.0 (W)Pth,1342
= 2.5 (W)
33.67%
12.29%
Simultaneous emission lights
(
intracavity
transmission
T=85.75%
)
Threshold
P
th,1064
= 3.5 (W)
P
th,1342
= 2.5 (W)
25.96%
3.92%
Slide9Hysteresis loop & pattern
Horizontal
Vertical
Horizontal
Vertical
Slide10Hysteresis loop V.S. pump power
5W
6W
7
W
5W
8
W
9
W
10W
Slide11Width of Hysteresis loop
T
L
T
H
Slide12SummaryNd:YVO4 & EO PPLN Bragg modulator
Slope efficiencies & thresholds based on T-type laser cavity: 1064 nm 25.96%, 3.5 W
1342 nm
3.92%,
2.5 W
The hysteresis loop region of the
transmission is from 64.88%
to 84.47% with pump power 9W.
The
width of
the hysteresis
loop increased
as the pump power
increased.
In the hysteresis region, the polarization-dependent pattern appears that the competition of these two wavelengths could be a two-dimensional behavior.
Slide130
30
40
60
90
120
140
150
180
1064nm pattern with polarization
Slide140
1342nm pattern with polarization
10
20
30
40
50
60
70
80
90
100
110
120
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140
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180