FraunhoferHeinrich Hertz InstituteFraunhofer
Heinrich-Hertz-Institut
Generation and Optical Processing of 100 GBd QAM Signalsof 100-GBd QAM Signals
Thomas Richter
Fraunhofer Heinrich Hertz Institute, Einsteinufer 37, 10587 Berlin www.hhi.fraunhofer.de
PhotonicNetworks and SystemsAcknowledgment
Research projects
SASER M ltiR FOPASASER MultiReg FOPA
All my collegues of the Submarine and Core Systems Group at Fraunhofer HHI
Lars Grüner Nielsen, OFS Denmark
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 2©
PhotonicNetworks and SystemsOutline
Introduction
Generation of 107-GBd QAM signals Generation of 107-GBd QAM signals Concept Experimental Results for BPSK/QPSK/16QAMExperimental Results for BPSK/QPSK/16QAM
Processing of 107-GBd QAM signals:All-optical Phase RegenerationAll-optical Phase Regeneration Concept Experimental Results for Nyquist-BPSKExperimental Results for Nyquist BPSK
Conclusions
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 3©
PhotonicNetworks and Systems
State-of-the-Art High-Speed Serial Systems Serial line rates in coherent systems
• Today’s commercial ~ 30-GBd QPSK (16QAM)• Lab (ETDM) 56-GBd 16QAM [Winzer, ECOC2010, PDP]
107-GBd 16QAM [Raybon, ECOC2013,PDP]
L b (T /R OTDM) 1274 GBd 16QAMx 10
• Lab (Tx/Rx-OTDM) 1274-GBd 16QAM [Richter, JLT 30(4) 2011]
Title of today’s talky“Generation and Optical Processing of 100-GBd QAM signals”• QAM-signals with high quality are preferred• ETDM system offer rather limited quality at ~100 GBd
Realization of high-quality 107-GBd QAM system
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 4©
g q y y
PhotonicNetworks and Systems107-GBd QAM-system: Key aspects
I/Q-mod. rate 53.5 GBd
Tx-OTDM2-fold
opt. Nyquistopt. Nyquistpulse-shapingcomm. avail. Rx-ADC
>120-GHz opt. BW
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 5©
PhotonicNetworks and Systems107-GBd System
107-GBd Nyquist BPSK/QPSK/16QAM Transmitter
53.5 GHz,33%-RZ 53.5 GBd 107 GBd
Nyquistshaping
CW MZM I/Q-Mod PS-OMUX OF
26.75 GHzclock
phase-stable53.5 GBd 107 GBddelay = 63 5 symbols
C-band~100 kHz
electrical 53 5 GBd delay = 63.5 symbols1178.1ps
electrical 53.5-GBddriving signals
2-ChannelBPG
(215-1)
D1
D2
to IQ-Mod
00 m
W/D
IVGeneration of the IQ-Mod driving signals: BPSK/QPSK
2-ChannelBPG
(215-1)
D1
D2
/D1
1
2
6dB
00 m
V/D
IV
to IQ-Mod
Generation of the IQ-Mod driving signals: 16QAM
(2 1)
BPSK: 0=0 bit, QPSK: 0=169 bit18.7 ps
90 (2 1)/D2 3
16QAM: 1=47 bit, 2=1071 bit, 3=1024 bit
6dB 10
18.7 ps
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 6©
PhotonicNetworks and Systems107-GBd System
107-GBd Nyquist BPSK/QPSK/16QAM Transmitter
53.5 GHz,33%-RZ 53.5 GBd 107 GBd
Nyquistshaping
CW MZM I/Q-Mod PS-OMUX OF
26.75 GHzclock
phase-stable53.5 GBd 107 GBddelay = 63 5 symbols
C-band~100 kHz
electrical 53 5 GBd delay = 63.5 symbols1178.1ps
electrical 53.5-GBddriving signals
2-ChannelBPG
(215-1)
D1
D2
to IQ-Mod
00 m
W/D
IVGeneration of the IQ-Mod driving signals: BPSK/QPSK
2-ChannelBPG
(215-1)
D1
D2
/D1
1
2
6dB
00 m
V/D
IV
to IQ-Mod
Generation of the IQ-Mod driving signals: 16QAM
(2 1)
BPSK: 0=0 bit, QPSK: 0=169 bit18.7 ps
90 (2 1)/D2 3
16QAM: 1=47 bit, 2=1071 bit, 3=1024 bit
6dB 10
18.7 ps
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 7©
PhotonicNetworks and Systems107-GBd System
107-GBd Nyquist BPSK/QPSK/16QAM Transmitter
53.5 GHz,33%-RZ 53.5 GBd 107 GBd
Nyquistshaping
CW MZM I/Q-Mod PS-OMUX OF
26.75 GHzclock
Phase-stable53.5 GBd 107 GBddelay = 63 5 symbols
C-band~100 kHz
electrical 53 5 GBd
Broadband Coherent Receiver63 GH
delay = 63.5 symbols1178.1ps
electrical 53.5-GBddriving signals
ADC OfflineProcessing
~63 GHz160 GS/sOSNR
VOASignal
~50 GHz
DSPBERADC
90o
Hybrid
LOCWMonitoring
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 8©
PhotonicNetworks and Systems107-GBd: Spectra w/o & w/ Nyquist
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 9©
PhotonicNetworks and Systems107-GBd: Spectra w/o & w/ Nyquist
BPSK107-GBd RZ
107-GBd Nyquist
-10
0
in d
B
-20
tive
pow
er i
120 GHz
100 50 0 50 100
-30rela
t
-100 -50 0 50 100norm. frequ. in GHz
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 10©
PhotonicNetworks and Systems107-GBd: Spectra w/o & w/ Nyquist
BPSK107-GBd RZ
107-GBd Nyquist
QPSK107-GBd RZ
107-GBd Nyquist53.5-GBd NRZ
-10
0
-10
0
in d
B
-20
10
125 GHz-20
tive
pow
er i
120 GHz
100 50 0 50 100
-30
100 50 0 50 100
-30rela
t
-100 -50 0 50 100norm. frequ. in GHz
-100 -50 0 50 100norm. frequ. in GHz
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 11©
PhotonicNetworks and Systems107-GBd: Spectra w/o & w/ Nyquist
BPSK107-GBd RZ
107-GBd Nyquist
QPSK107-GBd RZ
107-GBd Nyquist53.5-GBd NRZ
16QAM107-GBd RZ
107-GBd Nyquist
-10
0
-10
0
-10
0
in d
B
-20
10
125 GHz-20
10
122 GHz-20
tive
pow
er i
120 GHz
100 50 0 50 100
-30
100 50 0 50 100
-30
122 GHz
100 50 0 50 100
-30rela
t
-100 -50 0 50 100norm. frequ. in GHz
spectrally well-confined within ~125 GHz (20-dB bandwidth)
-100 -50 0 50 100norm. frequ. in GHz
-100 -50 0 50 100norm. frequ. in GHz
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 12©
PhotonicNetworks and Systems107-GBd: Optical Envelopes
QPSK 16QAMBPSK
18.7 ps
53.5-GBd33%-RZ
9.35 ps
107-GBdRZRZ
9.35 ps107-GBdNyquist
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 13©
(measured using an optical sampling oscilloscope with > 500-GHz bandwidth)
PhotonicNetworks and Systems107-GBd: BER Performance
BPSK
2
R)
4
3
-log(
BE
R
10 12 14 16 18 206
5 theory 107-GBd BPSK
OSNR in dB
~0.5 dBimplementation penalty at 1x10-3
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 14©
implementation penalty at 1x10
PhotonicNetworks and Systems107-GBd: BER Performance
QPSKBPSK
2
R)
2
R)
4
3
theory
-log(
BER
4
3
-log(
BE
R
12 14 16 18 20 22 246
5 107-GBd QPSK
theory
10 12 14 16 18 206
5 theory 107-GBd BPSK
OSNR in dB
~0.5 dBimplementation penalty at 1x10-3
OSNR in dB
~1.5 dB
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 15©
implementation penalty at 1x10
PhotonicNetworks and Systems107-GBd: BER Performance
QPSK 16QAMBPSK
2
R)
2
R)
2
R)
4
3
-log(
BE
R
4
3
theory
-log(
BER
4
3
-log(
BE
R
18 21 24 27 30 33 36 396
5107-GBd 16QAMtheory
12 14 16 18 20 22 246
5 107-GBd QPSK
theory
10 12 14 16 18 206
5 theory 107-GBd BPSK
OSNR in dBOSNR in dB
~0.5 dBimplementation penalty at 1x10-3
OSNR in dB
Error floor at ~ 10-4 ~1.5 dB
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 16©
implementation penalty at 1x10
PhotonicNetworks and SystemsConclusions: 107-GBd System
107-GBd BPSK/QPSK/16QAM
107 GBd Receiver 107-GBd Receiver• Single broad-band receiver (>120 GHz optical BW)• Standard DSP (offline processing)
• 107-GBd Transmitter• 53.5-GBd ETDM• Conventional 33%-RZ pulse carving• Phase-stabilized optical time-division multiplex (x2)
Well-suited test-bed for 107-GBd signal processing
• Optical Nyquist-shaping for tight spectral confinement
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 17©
PhotonicNetworks and SystemsOutline
Introduction
Generation of 107-GBd QAM signals Generation of 107-GBd QAM signals Concept Experimental Results for BPSK/QPSK/16QAMExperimental Results for BPSK/QPSK/16QAM
Processing of 107-GBd QAM signals:All-optical Phase RegenerationAll-optical Phase Regeneration Concept Experimental Results for Nyquist-BPSKExperimental Results for Nyquist BPSK
Conclusions
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 18©
PhotonicNetworks and SystemsProcessing of 107-GBd signals
High-speed + QAM increased OSNR requirementincreased OSNR requirement increased sensitivity to impairments
(e.g from inline-amplication, optical filtering, nonlinearities)
reduced reach
Ways out ?y improved Tx/Rx-DSP, improved FEC-codes usage of o/e/o regeneration / shorter o/e/o intervals all-optical in-line regeneration
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 19©
PhotonicNetworks and SystemsFocus: PSA
Phase-sensitive amplifiers (PSA) using fiber-optic parametric amplifiers
L i (1R)• Low-noise (1R)• Phase-regenerative (2R+)
A few references on 2R+ A few references on 2R+...• K. Croussore, JSTQE, 14(8), pp. 2003 • R. Slavik, Nature Photon. 4, 2010• J Kakande ECOC 2010 PD 3 3• J. Kakande, ECOC 2010, PD 3.3
Reports on BPSK/QPSK NRZ-signals ≤ 56 GBd
Here: Focus will be on 107-GBd Nyquist-BPSK 2 phase states (0, ), Nyquist-pulse-shape envelope
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 20©
PhotonicNetworks and SystemsPSA: Principle
Pump1 Pump2dual-pump fiber-optical PSAFour-Wave Mixing (FWM)
SignalSignal*
Signal
Pump1
ωωS ωP2ωP1
g
Pump2HNLF
S* = P1 + P2 - S
E ~ A e+jS + A e-jSEout ~ AS e+jS + AS* e jS
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 21©
PhotonicNetworks and SystemsPSA: Complex-field illustration
2
Ratio(Signal*/Signal) 0 Pump1 Pump2
Four-Wave Mixing (FWM)
As* = 0( ti A /A 0)
As=1, s = {0 ... }
0
1
( g g )
ture Signal
Signal*
Im{E }
(ratio As*/As = 0)
-1
0
quad
ra
ωωS ωP2ωP1
Im{Eout}
-2 -1 0 1 2-2
inphase
S* = P1 + P2 - S
Re{E t} E ~ A e+jS + A e-jSpRe{Eout} Eout ~ AS e+jS + AS* e jS
No Signal* no phase-sensitive behaviour
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 22©
PhotonicNetworks and SystemsPSA: Complex-field illustration
2
Ratio(Signal*/Signal) 0
Pump1 Pump2
Four-Wave Mixing (FWM)
As* = As( ti A /A 1)
As=1, s = {0 ... }
0
1
( g g ) 1
ture Signal
Signal*
Im{E }
(ratio As*/As = 1)
-1
0
quad
ra
ωωS ωP2ωP1
Im{Eout}
-2 -1 0 1 2-2
inphase
S* = P1 + P2 - S
Re{E t} E ~ A e+jS + A e-jSpRe{Eout} Eout ~ AS e+jS + AS* e jS
With Signal* PS-gain for in-phase componentPS tt ti f th d t t
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 23©
PS-attenuation for the quadrature component
PhotonicNetworks and SystemsPSA: Complex-field illustration
2
Ratio(Signal*/Signal) 0
Pump1 Pump2
Four-Wave Mixing (FWM)
As* = As( ti A /A 1)
As=1, s = {0 ... }
0
1
( g g ) 1
ture Signal
Signal*
Im{E }
(ratio As*/As = 1)
-1
0
quad
ra
ωωS ωP2ωP1
Im{Eout}
-2 -1 0 1 2-2
inphase
S* = P1 + P2 - S
Re{E t} E ~ A e+jS + A e-jSpRe{Eout} Eout ~ AS e+jS + AS* e jS
With Signal* PS-gain for in-phase componentPS tt ti f th d t t
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 24©
PS-attenuation for the quadrature component
PhotonicNetworks and SystemsPSA: Complex-field illustration
2
Ratio(Signal*/Signal) 0
Pump1 Pump2
Four-Wave Mixing (FWM)
As* = As( ti A /A 1)
As=1, s = {0 ... }
0
1
( g g ) 1
ture Signal
Signal*
Im{E }
(ratio As*/As = 1)
-1
0
quad
ra
ωωS ωP2ωP1
Im{Eout}
Ph i-2 -1 0 1 2
-2
inphase
S* = P1 + P2 - S
Re{E t} E ~ A e+jS + A e-jS
Phase squeezing
pRe{Eout} Eout ~ AS e+jS + AS* e jS
With Signal* PS-gain for in-phase componentPS tt ti f th d t t
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 25©
PS-attenuation for the quadrature component
PhotonicNetworks and SystemsExperiment:
Black-box Coherent107-GBdNyquist PM PSA ReceiverNyquistBPSK
PM
broadbandelectr. noise
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 26©
PhotonicNetworks and SystemsSet-up: PSA
OUTPump2 HNLFSlave
LaserPump- OUT
IN PZT
10%
CW
SOA WDM WDM
PD
10%
Pump-Locking PSA-Stage
PD
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 27©
PhotonicNetworks and SystemsSet-up: PSA – Pump locking
OUTPump2 Slave
Laser250 mA OUT
PZT
10%
CW
WDM WDM
10%
PSA-StageIN
SOA
P(pump1) ≈ - 5 dBm
Pump1 (100 kHz)
P(data signal) ≈ -16 dBm
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 28©
PhotonicNetworks and SystemsSet-up: PSA – Pump locking
OUTPump2 Slave
Laser250 mA OUT
PZT
10%
CW
WDM WDM
10%
PSA-StageIN
SOA
P(pump1) ≈ - 5 dBm 10
20
Pump1 (100 kHz)
pump1P(data signal) ≈ -16 dBm
-20
-10
0
wer
in d
Bm
pump1107-GBd
BPSK
1550 1552 1554 1556 1558 1560-50
-40
-30po
w
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 29©
wavelength in nm
PhotonicNetworks and SystemsSet-up: PSA – Pump locking
OUTPump2 Slave
Laser250 mA OUT
PZT
10%
CW
SOA WDM
10%
PSA-StageIN
WDM
Pump1 (100 kHz)
pump1pump2
Generation of a phase-locked dual-pump configuration by modulation stripping
107-GBdBPSK
and optical injection locking
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 30©
PhotonicNetworks and SystemsSet-up: PSA – HNLF
OUTPump2 HNLFSlave
Laser250 mA OUT
10% SOA WDM
10%
PD
IN PZTCW
WDM
OPLL-Circuit PD
HNLF
Pump1 (100 kHz)
OPLL- L=189 m, = 7.5 (W km)-1
- Al-doping & strain for suppressionof stim Brillouin scattering
- Sets the PSA operation point to achieve gain or attenuation
of stim. Brillouin scattering PSBS > 31 dBm- Compensates relative phase drifts
within the pump-locking stage
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 31©
PhotonicNetworks and SystemsResults: PSA – HNLF input
30R 0 01
1020
Bm
P(P1+P2) ~ 30 dBm
Res: 0.01 nm
107 GBd
20-10
0
wer
in d
B pump1107-GBdBPSKpump2
40-30-20
pow
1545 1550 1555 1560-40
wavelength in nm
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 32©
PhotonicNetworks and SystemsResults: PSA – HNLF output
30R 0 01
OPLL set for max-Gain
1020
Bm
Res: 0.01 nm PSA-input
20-10
0
wer
in d
B
PSA-gain(ON/OFF)
40-30-20
pow
( )
~ 5.3 dB
HNLF-loss
1545 1550 1555 1560-40
wavelength in nm
~ 4 dB
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 33©
PhotonicNetworks and SystemsResults: PSA – HNLF output
30
OPLL set for max-GainOPLL set for min-Gain (=max.Att.)
R 0 01
1020
Bm
PSA-input
Swing
Res: 0.01 nm
20-10
0
wer
in d
B ~ 20 dB
PSA-gain(ON/OFF)
40-30-20
pow
( )
~ 5.3 dB
HNLF-loss
1545 1550 1555 1560-40
wavelength in nm
~ 4 dB
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 34©
PhotonicNetworks and Systems
Results: 107-GBd Nyquist-BPSK IN/OUT
PSA preserves the Nyquist pulse-shape of the input signal !p yq p p p g(as also expected for unsaturated operation)
Bl k bBlack-boxPSA OUTIN
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 35©
PhotonicNetworks and SystemsResults: Phase-squeezing
increase in magnitude of applied broadband phase noiseincrease in magnitude of applied broadband phase noise
beforePSAPSA
after PSA
Phase distributionbefore PSA
202
er/b
efor
eto
r in
dB
A lit d-20-10
0
ty in
dB
after PSAbef.PSA (undegr.)
0.0 0.1 0.2 0.3 0.4 0.5
-6-4-2
Phase
atio
STD
afte
he re
gene
rat Amplitude
90 60 30 0 30 60 90-60-50-40-30
prob
abili
t
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 36©
ra th phase-STD of degraded signal-90-60-30 0 30 60 90
phase error in deg
PhotonicNetworks and SystemsResults: 4-Level Phase-Regeneration
107 GBd PSA107-GBdQPSK
107-GBdstar-8QAM PSA
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 37©
PhotonicNetworks and SystemsConclusion
Phase-regeneration in PSA has been applied to Nyquist-shaped signals Up to 6-dB phase-squeezing was achieved at 107-GBd
with Nyquist-BPSK Processing of more complex formats possible in modifiedProcessing of more complex formats possible in modified
PSA configurations
The investigations have been enabled by the presented107-GBd system• 53 5 GBd ETDM + 2 f ld OTDM• 53.5-GBd ETDM + 2-fold OTDM• 126-GHz coherent receiver• Modest implementation penalties for BPSK/QPSK/16QAM
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 38©
Modest implementation penalties for BPSK/QPSK/16QAM
FraunhoferHeinrich Hertz InstituteFraunhofer
Heinrich-Hertz-Institut
Generation and Optical Processing of 100 GBd QAM Signalsof 100-GBd QAM Signals
Thomas Richter
Fraunhofer Heinrich Hertz Institute, Einsteinufer 37, 10587 Berlin www.hhi.fraunhofer.de
PhotonicNetworks and Systems
Results: PSA – signal power atPSA output w/ & w/o phase-locking
5
OPLL-settingfor max.Gain OPLL OFF
(slow power fluctuations)
5
0
n dB
-10
-5
pow
er in
OPLL-settingfor max.Gain
-20
-15
rela
tive
OPLL-setting
0 10 20 30 40 50-25
time in s
OPLL-settingfor min.Gain
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 40©
time in s
PhotonicNetworks and SystemsPhase-regenerative PSA for QAM
Richter, IEEE Ph t i S i t
4-PAM2ASK BPSK Photonics Society
Summer TopicalConference 2013
PSA2ASK-BPSK
(20 GBd)
Star-8QAMRichter, ECOC 2013,We.3.A.2
PSA(25-GBd)
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 41©
PhotonicNetworks and SystemsBPSK-PSA: Complex-field illustration
Pump1 Pump2Four-Wave Mixing (FWM)
2 0 0.2Ratio(Signal*/Signal)ratio As*/As ↑
As=1, s = {0 ... }
SignalSignal*
0
10.4 0.6 0.8 1
ture
( g g )
Im{E }
ratio As*/As ↑
ωωS ωP2ωP1
-1
0
quad
raIm{Eout}
Ph i S* = P1 + P2 - S-2 -1 0 1 2
-2
inphaseRe{E t} E ~ A e+jS + A e-jS
Phase squeezing
pRe{Eout} Eout ~ AS e+jS + AS* e jS
Phase-squeezing strength is dependent on the FWM-efficiency
ISUPT2013, RochesterOctober 21, 2013
Thomas Richter 42©
q g g p y