Fonctions et intégration photoniques

Fonctions et intégration photoniques :
tendances émergentes
(FoncIntPhot)
Guang-Hua DUAN
Alcatel Thales III-V Lab
A joint Laboratory of "Alcatel Lucent Bell Labs" and "Thales
Research & Technology"
Campus Polytechnique, 1, Avenue A. Fresnel
91767 Palaiseau
Plan des Cours
• Intégration photonique
• Transmission WDM
• Motivations de l’intégration photonique
3H
• Source accordable en longueur d’onde
• Multiplexeur en longueur d’onde : AWG
Plan des Cours
• Modulateurs
• Modulation d’amplitude, modulation de fréquence
• QPSK
• QAM
• Photodétecteurs
• Photodiodes
• Récepteur cohérent
• Exemples des PIC sur InP
• Transceiveurs WDM
• Exemples des PIC sur silicium
• Briques de base
• Transceiveur pour applications courtes distances
3H
Plan
•
•
•
•
•
•
•
Pourqoui la fonction de modulation
Paramètres clés de modulateur
Modulation directe d’un laser
Modulateur Mach-Zehnder
Modulateur électro-absorption
Modulateur QPSK
Modulateur QAM16
Wavelength-selectable laser with MZM DB PIC
SG-DBR Laser
MZ
Modulator
Amplifier
Front
Rear
Mirror Gain Phase Mirror
MQW
active
regions
Sampled
gratings
Courtesy of JDSU
Optical Duobinary Transmission
0 km
20 0 km
Effet Stark Confiné Quantiquement
E0
V= 0
EV < E0
Polarisation inverse
Modulateur Electro-absorption
strong exciton effect: 31393- N o7
photocurrent
0,30
0,25
0V
-0,5V
0,20
-1V
-1,5V
0,15
-2V
-3V
0,10
-4V
-5V
0,05
0,00
1500
1520
1540
1560
1580
1600
wavelength
Longueur d ’onde d ’entrée
Pe ↑ → photocourant I ↑ → V ↓ → sensibilité de détection ↑→ photocourant I ↑
EAM for integration
• New trade-off between BW and ER with AlInGaAs QW
0,5
Enhanced exciton
structure
photocurrent
0,4
0,3
0,2
Steep Absorption
Edge
-5V
0,1
0V
0,0
1350
1450
1550
wavelength
1650
Electroabsorption in InP
Band edge moves to longer wavelength with an
applied negative voltage.
−
+
p
n
p-n junction is not absolutely
necessary, but need way to stop
carriers from bleeding through.
Bulk material “Franz-Keldysh effect”
MQWs “Quantum-confined Stark effect”
Electrorefraction in InP
Forward injection
p
n
Strong effect (carrier movement).
Slower than 1 ns.
Reverse voltage
−
+
p
n
Weak effect (Kramers-Kronig of EAM effect).
Faster than 10 ps.
p-n junction is not absolutely
necessary, but need way to stop
carriers from bleeding through.
Recently n-i-n junction was
demonstrated.
First transmitter PIC: EML
EML = electroabsorption-modulated laser
DFB laser
EAM
M. Suzuki, et al., J. Lightwave Technol., vol. LT-5, pp. 1277-1285, 1987.
Today’s EMLs
10-Gb/s small form-factor pluggable (XFP) transceiver
Transmitter optical
sub-assembly (TOSA)
DWDM XFP:
•~$2000
•3.5 W
•-1 to +3 dBm
•80 km
Receiver optical subassembly (ROSA)
Advanced modulation formats
Advanced modulation formats increase the capacity of a single fiber
Im
Im
OOK
BPSK
Re
b/baud = 1
Re
Im
QPSK
b/baud = 2
Re
Im
Im
16 QAM
TE
Re
Re
DP-QPSK
Im
TM
Re
b/baud = 4
OOK = on-off keying
BPSK = binary phase-shift keying
QPSK = quadrature phase-shift keying
QAM = quadrature amplitude modulation
DP = dual polarization
QPSK modulators traditionally made in LiNbO3 or GaAs
LiNbO3
T. Kawanishi, et al., paper OWH5, OFC 2007.
GaAs
R. Griffin, et al., paper FP6, OFC 2003.
Traveling-wave MZM DQPSK PIC
Sub-MZMs
I
I
π/2 phase shifters
50-Ω termination
Modulated
signal
CW
light
Q
Q
50-Ω termination
DC bias
Wavelength range: L-band (λPL = 1.47 µm)
RF input: Differential
EO interaction length: 3 mm (Sub-MZMs),
1.5 mm (π/2-phase shifter)
Chip size: 7.5 mm x 1.3 mm
Courtesy of N. Kikuchi
N. Kikuchi, ECOC, 10.3.1, 2007.
Uses novel
n-p-i-n
structure
Results
Driving voltage: 3 Vpp (Vπ ) for each
Received eye patterns
40 Gbit/s
data data
80 Gbit/s
+/-π/4
LD
40 Gbit/s
MZDI
data data
Fiber output power (dBm)
λ = 1580 nm
(+π/4)
Balanced
receiver
-10
-20
(-π/4)
-30
-40
(10 ps/div)
-50
-60
-70
-80
189.5
189.6
189.7
189.8
Frequency (THz)
Slide courtesy of N. Kikuchi
First InP multi-channel QPSK transmitter PIC
AWG
BER = 4E-4
Nested
MZM
Q
I
•10 frequency-tunable DFB lasers
with backside power monitors
•10(I) + 10(Q) nested Mach-Zehnder
modulator pairs
•1 AWG
•111 integrated elements in total on
chip
S. Corzine, et al., OFC, PDP18 , 2008.
D
F
B
υ Tunable
10 Log ( S21 ) (dB, optical)
3
PM
Slide courtesy of C. Joyner
21.5Gb/s NRZ
Balanced Receiver
Eye
A
S21 Frequency
Response
BER = 5E-4
0
-3
Small-signal BW > 20GHz
-6
-9
0
5
10
15
Frequency (GHz)
20
Phase vs. amplitude modulators
40-Gb/s phase modulator
4 mm
Data
RF and optical velocities difficult to match
(Can get away with lumped phase modulator up to ~10 GHz)
H. N. Klein, et al., paper TuA2.4, Integrated Photonics Research M 2006.
40-Gb/s amplitude modulator
100 µm
Data
Electro-absorption modulator (EAM)
Takes advantage of the quantum-confined Stark effect
B. Mason, et al., IEEE Photon. Technol. Lett., vol. 14, pp. 27-29, 2002.
QPSK generation using EAMs
Data 1
90°
EAMs
Data 2
Im
Optical PSK format using EAMs
first demonstrated in
Re
I. Kang, Opt. Ex., vol. 15, pp.
1467-1473, 2007.
QPSK using two EAMs
Data 1
225°
90°
Data 2
Im
Re
EAM chirp
OOK
Conventional push-pull MZM
EAM
Im
Im
Re
Re
No chirp
Significant chirp
QPSK
Conventional push-pull nested MZM
EAM-based
Im
Im
Re
Has chirp!
Re
Similar chirp
16 QAM modulator PIC
3.1 mm
Stretched vertically for clarity
EAM #1
-720-180°
0°
90°
-720-90°
EAM #3
EAM #2
Star coupler
0.17
0.33
0.33
0.17
EAM #4 Phase shifter/
attenuator
Pulse carver
EAM (not used)
Use same output inlet width for all four ports.
Input inlet width selected to achieve the 1:2:2:1 power splitting ratio.
The phase shifters were used only for testing and were not used in the experiment
C. R. Doerr, et al., OFC, PDP20 , 2008.
A 4 EAMs driven with independent data streams
Im
0.17
0.33
0°
180°
Re
0.33
0.17
-90°
90°
QAM-8 with electro-absorption modulators