High capacity transmission over transoceanic distances ... · PDF filee.g. 50 GHz space Frequency (Wavelength ... [7] 3-core MCF SC- EDFA 1.0T 4,200 0.004 OFC2012 [8] 7-core MCF

October 21, 2013 1

High capacity transmission over transoceanic distances with space-division-multiplexing

Itsuro Morita

KDDI R&D Laboratories Inc.,

October 21, 2013

Upcoming capacity crunch

2

October 21, 2013

Remaining orthogonal dimensions Space Division Multiplexing

Symbol rate spaceFrequency

imaginary

real

16QAMQPSK

e.g. 50 GHz space

Frequency(Wavelength)

QAMcos()sin() 256QAM

SpaceCore

single core multiple cores

SpaceMode

LP01 LP11a LP11b LP21a LP21b LP02 LP31bLP31a

Polarizationy

x Dual Pol.Single Pol.

3

TimeTimee.g. 10 Gbit/s 100 Gbit/s

October 21, 2013

Single-Core Fiber(SCF)

Multi-Core Fiber (MCF)Uncoupled MCF Coupled MCF

Single-Mode(SM)

Few-Mode(FM)

Multi-Mode(MM)

Optical fibers for SDM

4

October 21, 2013

MCF transmission experiments over 1000km

MCF: Multi-core (MC) fiberCDP: Capacity distance product

Fiber Amplifier Net bitrate[bit/s/fiber]

Distance[km]

CDP[Ebit/s·km] Year

7-coreMCF SC- EDFA 7.5T 2,688 0.020 ECOC2011 [7]

3-coreMCF SC- EDFA 1.0T 4,200 0.004 OFC2012 [8]

7-coreMCF MC-EDFA 28.8T 6,160 0.177 ECOC2012 [9]

7-coreMCF MC-EDFA 110.9T 6,370 0.706 2013 [10]

OPTICSEXPRESS

7-coreMCF MC-EDFA 140.7T 7,326 1.03 ECOC2013 [5]

12-coreMCF

MC-EDFA+Raman 688T 1,500 1.03 ECOC2013 [6]

SC-EDFA: Single-core EDFA, MC-EDFA: Multicore EDFA

October 21, 2013 6

Trans-oceanic class MCF transmission

Demonstration of trans-oceanic class space-division-multiplexing (SDM) transmission with MC-EDFA

40 x 128 Gbit/s transmission per core over 6,160km 7-core MCF- Total capacity : 28.8 Tbit/s per fiber- CDP : 177 Pbit/s･km

264 x 72 Gbit/s transmission per core over 6,370 km 7-core MCF- Total capacity : 111 Tbit/s per fiber- CDP : 707 Pbit/s･km

201 x 120 Gbit/s transmission per core over 7,326 km 7-core MCF- Total capacity : 140 Tbit/s per fiber- CDP : 1.03 Ebit/s･km

October 21, 2013 7






October 21, 2013 8

7-core MCF

Cross-section of MCF

Parameter Value# of cores 7

Cladding diameter 200 μmCore pitch 56 μm

Effective area (Aeff) 99 μm2

Attenuation loss 0.188-0.200 dB/kmChromatic dispersion 18.4-18.7 ps/nm/km

Span length 55 kmTotal span loss

incl. Fan-in/Fan-out11.4 to 12.3 dB

Core #1 is center core

End face of fiber bundle

MCF

Thin Fibers

Fiber Bundle

Fan-in/Fan-out

October 21, 2013 9

7-core MC-EDFA

Cross-section of 7-core MC-EDF[1]


Cladding diameter 180 μm

Core pitch 45 μm

Attenuation loss ~3.4 dB/m

Gain 15 dB

NF (typ.) incl. loss of Fan-in/out, WDM cpl. 7 dB

Gain and noise figure (NF)

Configuration

[1] Y. Tsuchida et al, ECOC2012, Tu4F2.

October 21, 2013 10

Crosstalk(XT) of MC-EDFA and MCF

XT of MC-EDFA (between 2 cores) XT of MCF (between 2 cores)

Core #1 is center core

Total XT of MC-EDFA at center core: < -46.5 dB (worst)

Total XT of MCF at center core : < -45.6 dB per span (worst)

Total XT per span at center core : < -43 dB per span (worst)e.g. Accumulated XT after 6,160 km transmission with 112 spans: < -22.5 dB

October 21, 2013

SWCore#1 in

#2 in

#3 in

#4 in

#5 in

#6 in

#7 in

GFF

GFF

GFF

GFF

GFF

GFF

PBC

AWGr

AWGr

ECL

DFB, ECL

Even ch.

Odd ch. 32 Gb/s PPGDATADelay

DATA

Delay

100‐50G IL

Delay

3dB

PMEI

Q

I

Q

IQM

IQM

……

Ch1Ch3

Ch39

Ch2Ch4

Ch40

Integrated pol.‐diverse hybrid Balanced

PDs

Real‐time oscilloscope

LO

ADC

ADC

ADC

ADC

Optical signal

11

Experimental setup

40 x 128-Gbit/s PDM-QPSK signals (SD-FEC with 20% OH) Received signal is processed offline 7 cores are connected sequentially using fan-in/fan-out[2]

[2]S. Chandrasekhar et al, ECOC2011, Th13C4.

TX RX

ECL: External cavity laserAWGr: Arrayed waveguide gratingIQM: IQ modulatorPME: Polarization multiplexing emulatorPBC: Polarization beam combinerGFF: Gain flatting filter

LO: Local oscillator ~100 kHz LWBalanced PD: Photo diodesADC: Analog/digital converter(50 GSa/s, 16 GHz bandwidth)

55 km MCF MC-EDFA

October 21, 2013 12

Transmission performance

Q-factor vs Transmission distance

The Q-penalty after transmission is about 1.4 dB The impact of XT is low even after 6,160 km transmission of MCF with

more than 100 MC-EDFAs

October 21, 2013 13


After 6,160 km transmission

All of channels surpassed FEC limit [1] with Q-margin of 1 dB Total capacity : 7-core x 40ch x 103.125 Gbit/s(net) = 28.8 Tbit/s per fiber CDP :177 Pbit/s x km

1550.116 nm 1558.173 nm 1565.905 nm

FEC limit = 6.4 dB

October 21, 2013 14






October 21, 2013 15

D

D

24GS/sAWG

IQM

IQM

Odd

Even

IQM132 lasers

37.5GHz space

8 lasers37.5GHz space

8 lasers37.5GHz space

IQM

18.75GHz

24GS/sAWG

Loading

PME

SW

GFF

GFF

GFF

core1

core2

core7

SW

1S

W7

SW

2

1x8

split

ter

Pol.-diversityoptical hybrid

BPDBPD

BPDBPD

Real-timeoscilloscope ECL

OBPF

7:1

switc

h

46 km MCFMC-EDFA

7 x 264 channel x 72 Gbit/s (111 Tbit/s) quasi-Nyquist-WDM PDM-QPSK signal transmission over 6,370 km

TX

RX

Experimental setup

October 21, 2013 16

5 10 2015OSNR (noise in 0.1 nm) [dB]

Single ChannelWDM

BER

10-1

10-2

10-3

10-4

10-610-5

20100-20 -10

Pow

er [1

0dB

/div

]

Frequency [GHz]

18GHz

WDM

Single channel

Quasi-Nyquist-WDM PDM-QPSK signal

Bit rate : 128 Gbit/s → 72 Gbit/sSpectral Efficiency : 2 bit/s/Hz → 3.2 bit/s/Hz

October 21, 2013 17

7-core MCF


Cladding diameter 196 μm

Core pitch 56 μm

Effective area (Aeff) 99 → 121 μm2

Attenuation loss 0.196-0.200 dB/km

Chromatic dispersion 18.4-18.7 ps/nm/km

Span length 55 → 45.5 kmTotal span loss

incl. Fan-in/Fan-out11.4 - 12.3 dB

→ 9.9 – 10.5 dB

2

13

5 4

6

7

trench index core profile0.40.2

0-0.2-0.4

-0.8-0.6

[%

]

0-20 -10 2010r [µm]

October 21, 2013 18

-80

-70

-40

-50

-60

Cro

ssta

lk [d

B]

2-1

2-4

2-6

1-3

1-5

1-71-

21-

41-

6

2-3

2-5

2-7 3-

1

3-6

3-4

3-2

3-5

3-7 4-

1

4-6

4-3

4-2

4-5

4-7 5-

1

5-6

5-3

5-2

5-4

5-7 7-

1

7-5

7-3

7-2

7-4

7-66-

1

6-5

6-3

6-2

6-4

6-7

Pair of cores

1550 nm

Crosstalk of MCF

Total XT of MCF at center core per span : < -45.6 dB → -51 dB

October 21, 2013 19

core1 core2core6core5

core4core7core3

05

10

15

25

20

3

4

5

7

6

NF

[dB

]G

ain

[dB

]

1530 1540 15601550Wavelength [nm]

7-core MC-EDFA

Single stage configuration→ Two stage configuration for higher output power- Bandwidth: 1.9 THz → 5 THz

NF<5.5dB

October 21, 2013 20

191 192 193 194 196195

周波数 [THz]

4

6

8

Q値

[dB]

FEC threshold : 5.9 dB

2

光パワー

[10dB

/div]

core1 core2core6core5

core4core7core3

Qfa

ctor

[dB

]

Frequency [THz]

Opt

ical

Pow

er [

10dB

/div

]

Capacity-Distance Product : 707 [Pbit/s x km]



October 21, 2013 21






October 21, 2013

Experimental Setup

GFF

GFF

GFF

45.5km MCFMC-EDFA

core1

core2

core7

SW

1S

W7

SW

2

Pow

er S

plitt

er

Pol.-diversityoptical hybrid

BPD

BPD

BPD

BPDReal-time

oscilloscopeECL

OBPF

7:1

switc

h

25GHz

Frequency

30GBaud

25GHz-spaced 201-WDM100Gbit/s DP-QPSK

with duobinary-pulse shaping(20%-overhead SD-FEC)

D

D

50GS/sAWG

IQM

IQM

Odd

Even

MZM101 lasers50GHz space

8 lasers25GHz space

8 lasers25GHz space

IQM

12.5GHz

t

t

t

50GS/sAWG

LoadingSWWSS

WSS

WSS

OSAPC

PME

PM

E

22

7 x 201 channel x 100 Gbit/s (140.7 Tbit/s) super-Nyquist-WDM signal transmission over 7,326 km

October 21, 2013

Duobinary-Pulse Shaping andMaximum-Likelihood Sequence Estimation

Duobinary-pulse shaping

Impu

lse

resp

onse

Time [1/baudrate/div]

OSNR

IQ map

DP-QPSK

after duobinarypulse shaping

2-3dB

Proposed by J. Li et al., J. Lightwave Technol., 30, 1664 (2012) [13].

sincfunction

delayedsinc

function

Q fa

ctor

MLSE

1

00/0

1/1

1/2

0/1

0/0

1/1

1/2

0/1

0/0

1/1

t = 0 t = 1/B t = 3/Bt = 2/B

Duobinary trellis

23

October 21, 2013

Back-to-Back Performance

Measured Bit-Error RatesOptical spectra of signalsP

ower

[10d

B/d

iv]

Duobinary-pulse shaping

Nyquist-pulse shapingSpectral overlap

Frequency [25GHz/div]

SC

SC

WDM

WDM

10 15 2520OSNR [dB]

WDMSC

WDMSC10-1

10-2

10-3

10-4

10-5

10-710-6

BE

R

Duobinary pulse shaping

Nyquist pulse shaping

Duobinary pulse shaping can suppress WDM crosstalk from adjacent channels.The penalty is around 2 dB compared with single-channel DP-QPSK.

Baudrate : 30GBaudWDM spacing : 25GHz

24

October 21, 2013

Transmission Performance

Q2 factors for all 1,407 channels (201-WDM, 7-Core) > 6.0dB

9

8

7

6

5

Q2

fact

or [d

B]

core1 core2core6core5core4

core7

core3

FEC threshold : 5.9 dB [14]

191 192 193 194 196195Frequency [THz]

Capacity-Distance Product : 1.03 [Exabit/s x km] 25


October 21, 2013

10 100

Transmission Experiments over 10Tbit/s・1,000km

10,000

Capacity per fiber [Tbit/s]

Dis

tanc

e [k

m]

1,000

1,000

5,000

2,000

High-capacity transmission experiments

Multi-core fiberSingle-core fiber

26

October 21, 2013 27

Reduction of power consumption

Multiple cores pumped by multimode LD w/o temp. control

Single Pump

Multiple-Pumps

Core in MC-EDFAPow

er C

onsu

mpt

ion Core pumped

MC-EDFA

Signals

Signals

Cladding pumped MC-EDFA

October 21, 2013 28

Summary

Demonstration of trans-oceanic class space-division-multiplexing (SDM) transmission with MCF and MC-EDFA

40 x 128 Gbit/s transmission over 6,160 km- Total capacity : 28.8 Tbit/s per fiber- CDP : 177 Pbit/s･km

264 x 72 Gbit/s transmission over 6,370 km- Total capacity : 111 Tbit/s per fiber- CDP : 707 Pbit/s･km

201 x 120 Gbit/s transmission over 7,326 km- Total capacity : 140 Tbit/s per fiber- CDP : 1.03 Exabit/s･km

October 21, 2013 29

Thank you !!

The part of this work was supported by “Research on Innovative Optical Fiber Technology” and

“R&D of Innovative Optical Communication Infrastructure”The author thanks NEC Corporation and Furukawa Electric Co.,

Ltd. for their contributions.

Documents

High capacity transmission over transoceanic distances ... · PDF filee.g. 50 GHz space Frequency (Wavelength ... [7] 3-core MCF SC- EDFA 1.0T 4,200 0.004 OFC2012 [8] 7-core MCF