2015 06 23 the most advanced repeater wdm nice 2015 original

© 2015 Xtera Communications, Inc. Proprietary & Confidential 1

Xtera Communications, Inc.

The Why’s and the How’s of the Most Advanced Repeater

Herve Fevrier

24 June 2015


•  Quick update on Unrepeatered Subsea

•  Repeatered Subsea: the Why’s and How’s of the most advanced repeater

Outline


•  Recent Evolution –  Reach and Capacity x Reach

•  Key Technologies –  Distributed Raman Amplification –  Remote Optically Pumped Amplifier (ROPA) –  Coherent Technology, DSP, FEC, … –  Ultra Low-Loss Fibers

•  Going from 0.175dB/km to 0.155… means 400km goes to 450km!

NOTE: Only subsea applications here

Unrepeatered Subsea Communications

250

300

350

400

450

500

550

600

650

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Distance (K

m)

Year

0

1

2

3

4

5

6

7

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Capacity x Reach (P

b/s -‐

Km)

Year

(a)

(b)


•  Cabled large Aeff fiber - G.654D fiber (Corning Vascade EX2000)

•  Commercial DWDM equipment

•  Transmit and Receive ROPAs on one fiber pair

•  Advanced ROPA architecture

•  1 x 100G over 556.7 km (90.2dB) and 4 x 100G over 523.2 km (84.8dB)

Long Distance / Low Capacity Unrepeatered

100G MXP λ1

100G MXP λ2

100G MXP λ3

100G MXP λ4

WSS

DCU

EOA 289.3 km or

255.8 kmROPA (F)

133.7 km

EOA

ROPA (B)

Residualpump

sharing

WSS

ForwardRaman

BackwardRaman

100G MXP λ1

100G MXP λ2

100G MXP λ3

100G MXP λ4

ROPA (B)

ROPA (F)

p

P’

133.7 km

-50

-45

-40

-35

-30

-25

-20

1558 1560 1562 1564 1566 1568

Pow

er (d

Bm

)

Wavelength (nm)

Input-0.2nm RBWOutput-0.2nm RBW

-50

-45

-40

-35

-30

-25

-20

1557 1559 1561 1563 1565 1567

Pow

er (d

Bm)

Wavelength (nm)

Input-0.2nm RBWOutput-0.2nm RBW

(a)

(b) (c)

ROPA (F)

ROPA (B)

ROPA (B)

ROPA (F)

Signal

Signal

Residual pump sharing

Backward Pump

Backward Pump

Forward Pump

Forward Pump


•  G.654D fiber (Corning Vascade EX2000)

•  Wide-band distributed Raman amplification

•  Receive ROPA

•  15 Tb/s (150 x 100G) unrepeatered transmission over 409.6 km (68.2 dB) covering 1531-1592nm spectrum

High Capacity Unrepeatered

45 C-Band (odd) DFBs

30 L-Band (odd) DFBs

45 C-Band (even) DFBs

30 L-Band (even) DFBs

100G Comb

100G Comb

100-GHzPM-AWG

: PM 3dB (50/50) coupler : 3dB (50/50) coupler

WSS-1

C-100G MXP

C-100G MXP

L-100G MXP

BackwardRaman

Forward Raman

EX2000 409.6 km (68.2dB)

ROPA

120.9 km288.7 km

LRA-1 LRA-2 LRA-3

WSS-2

C-100G MXP

C-100G MXP

L-100G MXP

1525 1535 1545 1555 1565 1575 1585 1595Wavelength (nm)

-25

-20

-15

-10

-5

0

5

1525 1535 1545 1555 1565 1575 1585 1595

Powe

r (dB

m)

Wavelength (nm)

(a)

(b) (c)

LRA-2 out LRA-3 out

12

14

16

18

20

22

24

1525 1535 1545 1555 1565 1575 1585 1595

OSN

R (d

B)

Wavelength (nm)

OSNR for 10CHs

OSNR for 30CHs

OSNR for 50CHs

OSNR for 100CHs

OSNR for 150CHs

6

7

8

9

10

11

12

1525 1535 1545 1555 1565 1575 1585 1595

Q (d

B) b

efor

e FE

C

Wavelength (nm)

Q for 10CHs

Q for 30CHs

Q for 50CHs

Q for 100CHs

Q for 150CHs

(a)

(b)


•  Extra pumping fibers

•  Transmit and Receive ROPA

•  1x100G over 607 km (97dB) and 1x10G over 632 km (101dB)

Ultra-Long Unrepeatered

signal-path

pump-path1

Erbium, 20ma b

c

pump-path2pump λ1pump λ2

signal

ab

c

a’Erbium, 12m Erbium, 12m

signal-path

pump-path1

pump-path2(a)

WSS

327.6 km for 100G

352.6 km for 10G transmission

EDFA

DCU

EDFA

128.0 km

128.2 km

128.7 km

151.4 km

154.2 km

151.7 km

ForwardROPA

BackwardROPA

DCU

EDFA

DCU

EDFA

100G or 10G line card

For 10Gtransmission

pump-path1

pump-path2

pump λ1pump λ2

signal

signal-path : Total 607.0 km for 100G / 632.0 km for 10G transmission

100G or 10G line card WSS

(c)

Forward ROPA

Backward ROPA

(b)


•  Intermediate site can be a ROADM

•  8x100G over 2 spans: SMF 303.5km (59.7dB) and PSCF 342.9km (60.8dB)

Unrepeatered over a Cascade of Two Very Long Spans

Fwd Pumps Bkwd Pumps

8 x 120 Gb/s PM-QPSK SMF 303.5Km. 59.7dB

DFBDFB

DFB

100G Card

100G Comb

DCM

PM M

UX

EOAEOA Filter for ASE suppression

Fwd PumpsBkwd Pumps

EOAPSCF 342.9Km. 60.8dB

SMF 303.5Km PSCF 342.9Km

-35

-30

-25

-20

-15

-10

-5

0

5

1556 1558 1560 1562 1564 1566

Pow

er (d

Bm

)Wavelength (nm)

Span-1 Input

Span-1 Output

Span-2 Output

(a)

(b)


Xtera Submarine Timeline: Commitment and Innovation

1st repeatered upgrade

1st unrepeatered upgrade

1st redeployment of repeatered cable

1st ROPA 1st turnkey project 1st 100G upgrade of repeatered system

Xtera incorporated

Azea incorporated

NXT 10G LH rep.

Nu-Wave XLS

20G long-haul repeatered Xtera + Azea

Nu-Wave Optima

40G long-haul repeatered 100G SD-FEC

100G long-haul repeatered Subsea repeater

•  Commitment to the submarine market

•  Innovation in technology and business approach

LOI for 9,400 km system

557 km 100G unrepeatered

Contract for 1,500 km system

1st repeater deployment

1998 2001 2004 2005 2006 2007 2011 2010 2012 2013 2014 2015

607 km 100G unrepeatered


The Why’s of the Most Advanced Repeater

Google Confidential and Proprietary

Capacity Scaling and Flexibility - What Next?

● Dry Plant - Getting close to Shannon limit○ Minor tweaks in FEC, implementation penalties, some NL

compensation, flexible modulation but no game changers

● Wet Plant (some combination of these to get 4-10x increase)○ More spectrum (C+L bands) : Uses existing fiber cabling

infrastructure

○ More fibers : Needs re-engineering of cabling infrastructure

○ More cores (SDM) : Needs significant maturity of multicore fiber and component ecosystem

“No ... this is not real”(but would be cool)Google Confidential and Proprietary

Capacity Scaling and Flexibility - What Next?

● Dry Plant - Getting close to Shannon limit○ Minor tweaks in FEC, implementation penalties, some NL

compensation, flexible modulation but no game changers

● Wet Plant (some combination of these to get 4-10x increase)○ More spectrum (C+L bands) : Uses existing fiber cabling

infrastructure

○ More fibers : Needs re-engineering of cabling infrastructure

○ More cores (SDM) : Needs significant maturity of multicore fiber and component ecosystem

“No ... this is not real”(but would be cool)


Optical Repeater for Subsea Cable Systems Launched at

Innovations: Mechanical Marine grade titanium. Compact, light and strong.

Electrical Improved powering enabling Raman amplification.

Optical Modular optical design. Optical bandwidth increased by 50%.

Manufacturability Flexible and simplified manufacturing process


•  Down to 8,000m

•  Up to 12kV

•  Up to 8 fiber pairs

•  Titanium alloy has strength comparable to that of steel, yet it is 45% lighter

•  The repeater is extremely compact and light and can pass through a marine plough

•  Optical amplifier modularity – up to 55nm optical bandwidth

•  Reliability: < 10 FIT per amplifier pair

Xtera’s Repeater


Optical Characteristics

-‐1

0

1

2

3

4

5

1540 1550 1560 1570 1580 1590 1600 1610

NF (d

B)

Wavelength (nm)

-‐4

-‐3-‐2-‐10123

1540 1550 1560 1570 1580 1590 1600 1610

Rel. Gain(dB)

Wavelength (nm)

•  Bandwidth > 55 nm

•  Tilt of ±2 dB possible

•  Noise figure <4dB


Repeater Manufacturing 1

!


Repeater Manufacturing 2


Repeater Transfer


Repeater Loading


Repeater Deployment (First Raman Repeater)


HUGO: Cable Re-lay for New Unrepeatered System … later “upgraded” to a repeatered system!

Porthcurno

Guernsey

Lannion

282 km

189 km

A cable repair with a repeater

instead of a joint box!


•  Long repeater spacing

•  Completion planned in 2H 2015

US Department of Defense New 1,500 km Repeatered Subsea Cable System


•  Dry plant: More to come in 2015 –  Flex-Rate card: 100 / 150 / 200G per optical carrier –  Improved performance: coherent technology, DSP, FEC, …

•  Unrepeatered: Stay tuned 100G at 100dB soon… (x2 each year for 10 years)

•  Wet plant: –  Branching unit: first release this year –  Repeater: 70nm bandwidth (2017 deployment)

More capacity, More flexibility

Conclusion Where are we going from here??

Maximizing Network Capacity, Reach and Value Over land, under sea, worldwide
