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


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


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


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]

11

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

14

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

16201600158015601540

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

16201600158015601540

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


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

Documents

Over one Pbit/s capacity optical transmission based on 400