ANTIMONIDE BASED LASER DIODES IN THE 2 - 2.7 µm

ANTIMONIDE BASED LASER DIODES IN THE 2 - 2.7 µm

ANTIMONIDE BASED LASER DIODES
IN THE 2 - 2.7 µm
WAVELENGTH RANGE
A. Vicet*, D. Barat*, J. Angellier*, M. Digneton*, A. Salhi*, Y. Rouillard*, S.
Guilet**, L. Le Gratiet** , A. Martinez** and A. Ramdane**.
*Centre d’Electronique et de Micro-Optoélectronique de Montpellier (CEM2), UMR CNRS 5507,
Université Montpellier II, 34095 Montpellier, a.vicet@univ-montp2.fr
**CNRS / Laboratoire de Photonique et de Nanostructures (LPN), Route de Nozay, 91460
Marcoussis
LPN
Outline
CEM2 : Antimonide based lasers and detectors
- Wavelength ranges : 2 – 2.7 µm edge emitting quantum well (DFB or not) lasers diodes
- 2.3 µm VCSLs and VECSLs
- 3.5, 4.5, 6.5 µm quantum cascade lasers
For :
- Tunable diode laser absorption spectroscopy (WMS, photo-acoustic, ICLAS…)
- Conter measures
- Free Space communications
• TDLAS and spectroscopy
• Antimonide based lasers
• DFB process
• Results 2 – 2.7 µm
TDLAS and spectroscopy
Line strengths of different species, HITRAN 96 modelisation
W avelength (µm )
10 8
6
4
2
1E-15
1E-25
1E-24
1E-23
1E-22
1E-16
1E-21
1E-20
1E-19
1E-18
1E-17
-2
Line strength (cm /mol.cm )
1E-17
1E-18
H2O
CO2
-1
1E-19
1E-20
NH3
CH4
HCl
HF
H 2S
CO
S O2
1E-21
1E-22
1E-23
1E-24
1E-25
2000
4000
6000
8000
10000
-1
W avenum ber (cm )
L.S. Rothman et al,J. of Quantitative Spectroscopy & Radiative Transfer 82 (2003) 5–44
Air transmission windows :
λ = 0.85 µm ; 1.0 µm ; 1.2 µm ; 1.6 µm ; 2.3 µm ; 4.0 µm ; 10.4 µm
Antimonide based lasers
Ec
AlSb GaSb
InSb
Ev
1 eV
InAs
• 1.8 - 4µm spectral range can be covered
• GaAlAsSb lattice matched to GaSb for cladding layers
• Type-I or type-II band alignment for GaInAsSb QW with GaAlAsSb
barriers
Band gap engineering
• High refractive index
Antimonide based lasers
Two laser structures for emission at 2.38 µm or 2.6 µm
2.0
1.6
1.6
1.3
1.3
1.0
0.7
0.3
0.0
-0.3
-0.7
2 claddings Al0.90Ga0.10As0.08Sb0.92 (1.5 µm )
. N-doped (2x1018 cm-3)
. P-doped (5x1017 cm-3 & 5x1018 cm-3)
1 waveguide Al0.25Ga0.75As0.02Sb0.98 (0.9 µm)
3 quantum wells Ga0.64In0.36As0.13Sb0.87 (11 nm)
Energy (eV)
2.0
1.0
0.7
0.3
0.0
-0.3
-0.7
2 claddings Al0.90Ga0.10As0.08Sb0.92 (0.9 µm )
. N-doped (2x1018 cm-3)
. P-doped (5x1017 cm-3 & 5x1018 cm-3)
1 waveguide Al0.25Ga0.75As0.02Sb0.98 (0.9 µm)
2 quantum wells Ga0.64In0.41As0.08Sb0.92 (14 nm)
Single frequency emission
Lateral direction
Transverse direction : d active zone < 1µm
monomode
Lateral direction : calculation of w (edched ridge) and p( etch
depth)
monomode
Longitudinal direction : need a spectral filter to get single
frequency emission
Longitudinal direction
Transverse direction
w
V303 : T= 20°C
I = 100 mA
10000
p
CEM2 process: wet etching,
Mature and well adapted
No spectral filter (or accident !)
Isotropic etching
no vertical sidewalls
P (u.a.)
1000
100
10
Femlab modelisation
1
2.43
2.44
2.45
2.46
λ (µm)
Solutions ?
Coupled cavities (C3 lasers)
External cavities – grating coupling
Multi-sections lasers - DBR
DFB
2.47
DFB process, λ = 2.65 µm
A collaboration with :
LPN
Study and realisation of DFB antimonide based lasers
Complete developpement of a technological process
Lateral coupling*
Complex coupling of the evanescent part of the
guided mode
No regrowth needed
RIE or ICP dry etching
vertical side walls
1st order (k=1) Cr grating deposition on each side of the ridge
Λ
Λ=
⋅λ
⋅
* M. Kamp et al. Optical Materials, 17(1-2) (2001) pp. 19-25
Results 2 – 2.7 µm
0
LPN
P (a.u)
2002
0.1
-5
-10
2006
-15
2004
2003
0.01
2.0
2.1
2.2
2.3
2.4
λ (µm)
2.5
-20
2.6
2.7
-25
2.8
P (dB)
1
Line strength (cm /mol.cm )
Results 2 – 2.7 µm
-2
1E-17
1E-18
-1
1
1E-20
CO2
0
-5
1E-22
1E-23
1E-24
2.1
2.2
1E-18
HF
NH3
CO
N2O
1E-19
CH4
SO2
0.1
2.0
2.3
2.4
2.5
2.6
2.7
2.8
-10
1E-17
P (dB)
-2
-1
H2O
1E-21
P (a.u)
Line strength (cm /mol.cm )
1E-19
-15
1E-20
1E-21
0.01
1E-22
-20
1E-23
1E-24
2.0
2.0
2.1
2.1
2.2
2.2
2.3
2.3
2.4
2.4
2.5
2.5
2.6
2.6
2.7
2.7
-25
2.8
2.8
λ (µm)
Many wavelengths between 2 and 2.7 µm – many gazeous species
λ = 2.3 µm
1.0
Transmission
7
6
P (a. u.)
5
4
3
T = 25°C
Transmission
2
T = 35°C
1
0
0
20
40
60
80
100
120
140
I (mA)
1.0
0.8
0.6
Laser 13-15 35°C
0.4
80
100
1.0
120
140
160
120
140
160
0.8
0.6
Laser 13-15 25°C
0.4
80
100
I (mA)
2.308
0.9
2.306
0.8
2.304
Lambda (µm)
Transmission
Results 2 – 2.7 µm
0.7
0.6
Data1_1508 T = 22°C
Data1_1312 T = 30°C
Data1_1315 T = 35°C
2.302
2.300
2.298
0.5
0.4
2.302
2.296
!"
2.304
2.306
wavelength (µm)
2.308
60
80
100
120
I(mA)
140
160
λ = 2.6 µm
Results 2 – 2.7 µm
2.604
T=15°C
T=20°C
2.603
2.602
∆λ = 2 nm
λ (µm)
2.601
2.600
2.599
∆λ = 3 nm
2.598
2.597
110
120
130
140
150
I (mA)
Diode down DFB n°3
Diode DFB n°3
0.042
7
0.040
6
0.038
5
0.036
4
0.034
∆λ/∆
3
2
1
0.032
∆λ / ∆
0.030
0
90
95
100 105 110 115 120 125 130 135 140 145 150 155 160
0.028
100
110
120
130
140
150
160
Results 2 – 2.7 µm
Tuning properties : mainly thermal effects
T , neff , λ
Give acces to thermal resistance : Rth Tlaser = Theader+Rth.Pth
I=70mA
I=100mA
I=140mA
308
Temperature (°K)
307
306
305
304
303
302
301
300
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
Time (s)
22
Temperature (°C)
21
20
19
18
17
16
15
0
20
40
60
80
100
Injected current (mA)
120
140
160
0.1
Results 2 – 2.7 µm
Laser regime Cw and RT
Low threshold current (< 40 mA)
Laser linewidth = few MHz
Temperature tuning rate (1 mode) = 0.2 nm/K
Current tuning rate (1 mode) = 0.04 nm/mA
High SMSR (> 25dB)
Measured life time = 15000 h
Antimonide based lasers
P. Werle et al., Optics Lasers in Engineering 37 (2002) 101–114
Antimonide based lasers
6.1 Å semiconductors
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