Over one Pbit/s capacity optical transmission based on 400 ...
Transcript of Over one Pbit/s capacity optical transmission based on 400 ...
Over one Pbit/s capacity optical transmission based on 400 Gb/s channel and beyond
Oct. 21st 2013
Yutaka Miyamoto
NTT Network Innovation Laboratories, NTT Corporation
The 6th International Symposium on Ultrafast Photonics Technologies (ISUPT 2013)
2
Acknowledgement
The author thank the collaborative contributions ofFujikura, Hokkaido Univ., Osaka Pref. Univ.,Shimane Univ., and Technical Univ. of Denmark.
Part of this research uses results from researchcommissioned by the National Institute ofInformation and Communications Technology(NICT).
NTT Network Innovation Laboratories 3
Outline
Background
Crosstalk-managed multi core fiber transmission for Pbit/s-class capacity
I Choice of modulation format and Core Arrangement of MCF
II Propagation Direction Interleaving and Double Ring Structure MCF
Summary
4
100 M
1 G
10 G
100 G
1T
10 T
100 T
1980 1990 2000 2010 2020
1 P
Year
Cap
acity
per
fibe
r [b/
s]
★
★
★
★Electrical
TDM
WDM & Optical Amplification
:Research (without SDM)★
:Commercial system
Digital coherent &Multi-level modulation
★ :Research (with SDM)
★★
Space-division multiplexing
★★
★
Capacity trend in optical transmission systems
NTT Network Innovation Laboratories 5
Transmitter nmulti core
fiber
Transmitter1
Receiver n
Receiver1
multi coreamplifier
Fan-indevice
Fan-outdevice
Fundamental configuration of multi core Fiber Transmission
Multi core Fiber Multi core Connection
Fan-in/Fan-out device, Connector, Splicing Multi core Amplifier High spectral-efficiency digital modulation/demodulation
6
Multi core transmission
Nocoupling
Coupling
Strongcoupling
Super Mode
Weekcoupling
Crosstalk management
Classification of Multi core fiber transmission
7
Issues for Ultra high capacity MCF transmission
Modulation and Demodulation with Signal processing Ultra low power and large scale integration High spectral efficiency (multi-level, Spectrum narrowing) High OSNR tolerance
Crosstalk management High aggregated SE by optimizing the combination of the number
of cores (N) and multiple level of QAM
Multi core fiber High number of cores, Low loss, Low crosstalk, Low nonlinearity Broadband
Connection (FI/FO, connector, splicing) Low loss, Low crosstalk, High power tolerance, High return loss
Research on Innovative Optical Fiber Technologies(2010~2012)
Basic research of innovative fiber Design and fabrication method
of multi core fiberEvaluation of multi core fiber and roadmap towards penetration
R&D of Innovative Optical Communication Infrastructure (2011~2015)
1000 x capacity in the next decadeMulti core amplifierMulti core connectionMulti core/multi-mode transmission
NTT Network Innovation Laboratories 8
Japanese Research Activities forEXAT: Extremely Advanced Transmission
Commissioned by NICT(National Institute of Information and Communications Technology)
EXAT proposed 3M Technologies in 2008T. Morioka , 1st EXAT Initiative meeting in Jan. 2008
Ad Hoc Technical Committees (EXAT) under IEICE since 2010
NTT Network Innovation Laboratories 9
Outline
Background
Crosstalk-managed multi core fiber transmission for Pbit/s-class capacity
I Choice of modulation format and Core Arrangement of MCF
II Propagation Direction Interleaving and Double Ring Structure MCF
Summary
R&D efforts on high capacity transmission using space division multiplexing beyond 1 Ebps x km
Agg
rigat
eC
apac
ity p
er fi
ber
(Tbp
s)
Transmission Distance (km)100101
1
10
100
1000
1000 10000
10000
Single core fiber(Conventional)
10
Capacity limitof single core fiber
Multi core and Multi-mode fiber
[5]Multi mode fiberwith single core
[4]
[1] J. Sakaguchi et al, OFC2012 PDP 5C.1, 2012, [2] H. Takara et al, ECOC2012, Th.3.C.1. 2012. [3] T. Tsuritani et al, ECOC2012, Th.3.C.3. 2012.[4] V.A.J.M. Sleifferng et al., ECOC2012, Th.3. C.4. 2012. [5] D. Qin et al.. FiO 2012, PD FW6C.3, 2012 [6] A.Sano et al. Optics Express Vol.21(14), 16777-16783 (2013).[7] K. Igarashi et al., Optics Express, Vol. 21, (15), pp.18053-18060 (2013). [8] K. Igarashi et al., ECOC2013,PD3.E.3 (2013) [9] T. Kobayashi et al. ECOC2013, PD3.E.4 (2013.
Multi core fiberwith single-mode core
(bidirectional)
[6] Multi core fiberwith single-mode core
[2]
[3]
[1]
[7] [8]
[9]
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Crosstalk management IChoice of modulation format & Core arrangement of MCF
Aggregate spectral efficiency (SE) of MCF transmission = Number of Core: N x spectral efficiency / fiber:
1
10
1 10
20
30S
pect
ral e
ffici
ency
pe
r cor
e (b
/s/H
z)
Number of cores, N
XT<-30.6dB
XT < -17dB
32QAM(XT0.5-29dB)
QPSK(XT0.5-19dB)
16QAM(XT0.5-26dB)
This work[2]XT <-32dB
256QAM(XT0.5-38dB)
64QAM(XT0.5-32dB)
Single channel exp.WDM exp.Aggregate SE
XT -35dB
Issues: the trade off between low crosstalk andlarge effective area performance under limited cladding diameter.
12
One-ring-structured 12-core fiberMeasures to reduce inter-core crosstalk
• core to core crosstalk : Trench assisted structure• the worst crosstalk : One ring structure
Cores of one ring structure have only two adjacent cores.The small number of adjacent cores is helpful to reduce the degradation of crosstalk for all-core excitation.
‐60
‐50
‐40
‐30
‐20
Crosstalk[dB]
Core to core crosstalk
1625 nm
1550 nm
Core Pitch = 36.9 m
Cladding diameter = 225 m
Marker
Attenuation at 1550 nm 0.199 dB/km
Aeff at 1550 nm 80.7 m2
CD at 1550 nm 19.3 ps/nm/km
Crosstalk at 1550 nmCrosstalk at 1625 nm
<‐45 dB<‐35 dB
7
2 3
4
56
1
Maximum number of neighbor cores
6 6 2
Conventional MCFs Proposed MCF
S. Matsuo et al., Opt. Express 2012 Dec 17;20(27):28398-408
13
Loss with FI/FO: 12.4-14.8 dB
First 1 Pb/s Transmission Experiment over 52km
456.8Gb/s/ch. PDM 32-QAM SC-FDM signal(net data rate: 380Gb/s)
Wavelength (0.1nm/div.)
Power
(10d
B/div)
50GHz
84.4 Tb/s WDM spectrum after 52.4 km
50GHz-spacing 222ch. WDM
162016001580156015401520
Wavelength(nm)
Optical pow
er
(10d
B/div)
11 THz
1.01-Pb/s Capacity = 222-ch. WDM x 380 Gb/s x 12 coreAggregate SE : 91.4 b/s/Hz (7.6 b/s/Hz/fiber x 12 cores)
1:4 Rx
C+L+
111C
h
Tx1
Tx2
CPL PolMUX OTF
Signal under testECL
1:4
1:4
1:2
1:2
12:1
Fan
-in
1:12
Fan
-out
C+L+
C or L+
111C
h
OTF
SwitchFusion splice
Fusion splice
12-core MCF52 km
(NTT, Fujikura, Hokkaido Univ. DTU)
[2] H. Takara et al, ECOC2012, Th.3.C.1. 2012
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Small diameter fiberV-groove substrate12-core fiber
MCF and small diameter fibers are connected via a V-groove substrate.
Insertion loss: < 1.1 dBCrosstalk: -57dB
@1550 nm
35 mm
4 mm
3 mm
Compact FI/FO device was developed with low insertion loss and low crosstalk.
V-groove-type fan-in/fan-out device
15
Crosstalk of MCF with FI/FO
By employing the low crosstalk MCF and FI/FO devices, the crosstalk from all other cores of less than -32 dB was obtained.
Thanks to low crosstalk MCF and FI/FO devices, The Q-factor penalty of after 52-km transmission was within 0.22 dB.
-40
-38
-36
-34
-32
-30
16201600158015601540
0.5
0.4
0.3
0.2
0.1
0.0
Wavelength (nm)
Cro
ssta
lk (d
B)
Cro
ssta
lk p
enal
ty (d
B)
(Cor
e2)
-32
16
10
9
8
7
6
Q-fa
cto
r (d
B)
162016001580156015401520Wavelength (nm)
core1 core2 core3 core4 core5 core6 core7 core8 core9 core10 core11 core12
X-pol.
Y-pol.
Ch60, Core1,sc‐6
FEC threshold : 6.75 dB
1.01 Pbps transmission performance after 52-km 12-core multi core fiber
Q-factors of all 222 channels for 12 cores were better than Q-limit. 1.01-Pb/s transmission over 52-km MCF
with the highest aggregate SE of 91.4 b/s/Hz (7.6 b/s/Hz x 12 cores)
Crosstalk management IIPropagation Direction Interleaving (PDI) and Dual-Ring Structure (DRS)
• DRS can offer a larger core pitch for the same cladding diameter compared with ORS.• 30% extension in Aeff & 7.7-dB XT suppression was achieved.
One-Ring Structure (ORS) [4] Dual-Ring Structure (DRS)
This work[4]: H. Takara et al., ECOC2012, Th.3.C.1
-55
-50
-45
-40
-35
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Wavelength (nm)
XT
(dB
)
Unidirectional
PDI
• Propagation-Direction Interleaving reduces XT by ≥4dB.
Core1, 2 Core
3, 4
7, 8
11, 12
5, 6
9, 10
123
4
6 8
10
12
5
79
11
Alternating the propagation direction between adjacent cores
XT reduction from the closest cores.
Propagation direction interleaving (PDI)
[6] A. Sano et al., Optics Express 21(14), 16777-16783 (2013).
Single-channel transmission with PDI in 12-core MCF
10
9
8
7
6
510008006004002000
Distance (km)
Q (d
B)
Core4 only
1615.26 nm20GbaudPDM-
32QAMSingle-channel
• Unidirectional: 0.6-dB Q-penalty was observed at 500 km. • PDI: Q-penalty was successfully suppressed to 0.1 dB.
Core2-5Unidirectional
Core2-5PDI
Measured core(Core4)
2 x 344 Tb/s Propagation-direction Interleaved Transmission over 1500-km MCF with DRS
1x3 splitter
Core 1, 6, 9
DGE
1x12
sw
itch
Core 1
Core 6
Core 9
Core 2, 5,10
Core 4, 7,12
Core 3, 8,11
FI FO1x4
split
ter
TATT
PBS
ILF
CP
L
PS
ILF
IQM
CoherentRx
C or L+
SW
SW
Raman
Raman
Raman
IQM
OTF
ECL Signal under test
D1D2
D3D4
D5D6
D7D8
D9D10
D11D12
C & L+
EDFA
OTF
SW
SW
SW
SW
DAC DAC
D0
MZM
MZM
12.5GHz ClockDAC DAC
SW
11.5Gbaud, 16-QAM Transmitter
11.5 Gbaud Nyquist-pulse-shaped PDM-16QAM signal with roll-off factor of 0.01
748 WDM channels with 12.5-GHz spacing utilizing C- and L+-band Spectral efficiency of 6.13 b/s/Hz/core assuming 20% FEC overhead Total capacity of 2 x 344 Tb/s
Re-circulating loop PDI and core-to-core signal rotation scheme Improved worst noise figure of C-band multi-core-EDFA by 0.5 dB Reduced connection losses of fan-In/fan-out (FI/FO) devices by 0.3 dB
Receiver Multicarrier Full Electric-field Digital Back Propagation (DBP)
50.1km MCF
Double ring 12-core fiber
by Fujikura & Hokkaido Univ.
[9] T. Kobayashi et al., ECOC2013, PD3.E.4 (2013).
Multi-carrier full electric-field Digital Back Propagation (DBP)
CDcomp
.
Phaserot.
Calc.Coefficien
t
x Nstep
Fron
tend
err
or
corr
ectio
n1s
tLP
F
2nd
LPF
Re-
sam
ple
AE
QFr
eq. o
ffset
com
p. DEC.
DEC.
DBPO
ptic
al F
ront
end
&A
DC
sLO
Sig.
Inter- and intra-channel nonlinearities can be simultaneously compensated by back-propagating one nonlinear Schrödinger equation [9-11] .
[10] L. Zhu et al., Electron. Lett. 46(16), 1140-1141 (2010)[11] N. K. Fontaine et al., ECOC2013, Mo.3.D.5
Using identical coherent receiver to receive several WDM channels
Extraction of contributed subcarriers in DBP by 1st LPF.
[9] T. Kobayashi et al., ECOC2013, PD3.E.4 (2013).
Q-improvement in nonlinear tolerance by DBP
6.4
6.2
6.0
5.8
5.6
543210
Q-f
acto
r (d
B)
Number of contributing WDM channels in DBP
Linear equalization
Q-limit
Q ~0.7 dB
Wavelength: 1554.85 nm, Pin: -9dBm/ch, 748ch WDM configurationAfter 1500 km transmission
Q-improvement of 0.7 dB is achieved with three contributing channels.
Received optical spectra after 1500-km PDI transmission
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Wavelength (nm)
Opt
ical
pow
er (
10dB
/div
)
57 Tbit/s/core WDM spectra after 1500 km transmissionSE: 6.13 b/s/Hz/corePin : -9 dBm/ch
Through the re-circulating loop group of cores 1-6-9
Pow
er
(10dB
/div
)
1575.41575.21575.01574.81574.6
0.5 nm resolution
0.01nm resolution
12.5GHz grid
2x344 Tbit/s PDI transmission performanceafter 1500-km DRS-MCF transmission
Wavelength (nm)
Q (d
B)
1582.87nm, Core3
X-pol.
Y-pol.
• Q-factors of all 8976 channels (12core x 748ch) were better than Q-limit of 5.7 dB
• 2 x 344 Tb/s bidirectional transmission over 1500-km MCF• Record Capacity Distance Product per fiber of 1.03 Ebit/s x km
Q-limit
Challenges toward the SDM system with more than 100 multiplicity
Issues: the trade off between low crosstalk andlarge effective area performance under limited cladding diameter.
At = N x Aeff(SMF)=80m2
10 20 100
-50
-30
-20
0
Est
imat
ed C
ross
talk
(XT)
af
ter 1
000k
m (d
B)
Normalized total effective area At of MCF with N cores
N=7
7
-40
-10
N=19C-bandL-band
16QAM
QPSK
32QAM64QAM
8QAM
Allowable XT (Pe=0.5dB)
2 50
Scaling Technologiesare needed
SDM systemwith 30 -100multiplicity
Aeff(MCF)Aeff(SMF) QAM: Quadrature Amplitude Modulation
MCF: Multicore fiber, SMF:Single Mode Fiber12
N=12
NTT Network Innovation Laboratories 25
SDM based on MCF is a promising to increase the transmission capacity of optical fiber.
Interoperability of low crosstalk multi core fiber and connection technology is demonstrated for 7 core MCF transmission.
High-SE signal generation using multilevel modulation and crosstalk management are also key issues.
MCF transmission with the capacity scaling up to 1 Pbpshave been demonstrated.
Research and development of MCF transmission is needed for the capacity scaling of the future metro/core networks
- massive integration technologies for cost effectiveness- more capacity scaling SDM scheme beyond 1 Pbit/s- new network node functionality fully utilizing SDM nature
Summary