Fiber Technology Trends for Next Generation Networks

Christopher ToweryCorning Optical Communications

May 28th 2015

[email protected]

IV Towards Terabit per Second Optical NetworkingInternational Workshop on Trends in Optical Technologies

Optical Fiber 2.

© 2015 Corning Incorporated ..

Outline

• Hero Experiments and Technology Trends

• Quasi-Single Mode Fibers

• Submarine Network Evolution

• Un-repeatered and long span terrestrial applications – Extending the network through challenging terrain

• Extending systems reach in a legacy network

Optical Fiber 3.


Capacity-distance reach shows signs of consistent growth, however, no new records were set (534 Pb/s x km is still max.)

SDM = Multi-core fibers + Few-mode fibers

OFC 2015

Optical Fiber 4.


No records observed in total capacity either in SMF or SDM (FMF and MCF) fibers

• Appetite for hero SDM transmission experiments seems to be fading (see red points)…

• …But there was an increased number of results related to components and fiber designs to enable SDM transmission (not reflected in the graph)

OFC 2015

Optical Fiber 5.


What are the CDN’s saying about submarine networks?-- More capacity…..

Optical Fiber 6.


CDNs could be very large, their backbone is global, resembles submarine network with “long, big pipes”

~10,000 km ~5,000 km

~5,000 km

V. Kamalov et. al. ECOC 2014

Optical Fiber 7.


Using more modes to get higher capacity2 related approaches

7

• Few-mode fibers are considered for mode-multiplexed transmission with MIMO receivers

• Requires major transformation of the optical communication infrastructure • Benefits of the parallelism brought by MDM is not well established• Signal processing complexity is significant, and scales with transmission distance

[1] F. Yaman et al., Opt. Express, 18, 21342-21349 (2010).[2] J. D. Downie et al, Opt. Express, 19, B363-B369 (2011).[3] Q. Sui et al, Opt. Express, 23, 3156-3169 (2015).

• Few-mode fibers can be used for Quasi-single mode (QSM) transmission:• FMFs can be used for the benefit of their larger effective area.• FMFs can be incorporated into the existing single-mode infrastructure if signal is transmitted only in the

fundamental mode. • QSM suffers from multi-path interference (MPI). However, MPI can be mitigated with DSP.

Optical Fiber 8.


• In traditional single-mode fibers the light propagates in the fundamental mode, which is the only mode supported in the fiber

• In quasi-single mode fibers, the light is “forced” on a fundamental mode

Tx Rx

Tx Rx

How does a Quasi-Single Mode Fiber work?

Optical Fiber 9.


Quasi-single mode transmission with hybrid spans

9

FMF

Splice Splice

SM-EDFA SM-EDFA

Low DMA

High DMA

Single-mode fiber

[1] F. Yaman et al., Proc. OFC’13, paper OTu1D.2 (2012).[2] Q. Sui et al, Opt. Express, 23, 3156-3169 (2015).

[2]

Power

Span Length

Splice

MPI

Span Length

[1]

DMA:= Differential modal attenuation

Optical Fiber 10.


Technology – Ultra-Large Aeff

OFC 2015 post-deadline paper demonstrates record SE over Trans-Atlantic distance using Quasi-SMF fiber

Optical Fiber 11.


Hybrid Spans

11

Fiber Length (km) Atten (dB/km) Loss (dB)

Span1 102.82 16.5

FMF 51.15 0.154

Vascade®

EX300051.67 0.149

Span2 101.75 17

FMF 51.4 0.16

EX3000 50.35 0.157

Span3 100.01 16

FMF 51.4 0.156

EX3000 48.61 0.156

Span4 102.17 16.7

FMF 51.15 0.16

EX3000 51.02 0.154

Span5 101.43 16.2

FMF 51.4 0.156

EX3000 50.03 0.153

x5

FMF Vascade®

EX3000Bridge Fiber

Parameters FMF Vascade®

EX3000Effective

Area~200 µm2 150 µm2

Supported Modes

LP01, LP11

Diff. ModalAttenuation

0.3-0.5 dB/km

Diff. ModalGroup Delay

~0.93 ns/km

• Vascade® EX3000 is used as bridge fiber between FMF and amplifier pigtail.

• Tapered splicing is used between all splice points between dissimilar fibers

• Average loss from the total of 4 splices and two connectors are 0.7 dB.

Optical Fiber 12.


-20 -15 -10 -5 0 5 10 15 20

-35

-30

-25

-20

-15

-10

-5

0

Time (ns)

|H11

|2 (dB

)

All-single-mode fiberAll-few-mode fiberHybrid

All-SMF vs ALL-FMF vs Hybrid spans

Hybrid has less MPI

All-Single-Mode Fiber Loop All-Few-Mode Fiber Loop Hybrid span Loop

16 17 18 19 20 21 22 23 24 25 26 272

3

4

5

6

7

8

9

Received OSNR @ 0.1 nm (dB)

Q (

dB)

4060 km

All-single-mode-fiber

16 17 18 19 20 21 22 23 24 25 26 272

3

4

5

6

7

8

9


Q (

dB)

4060 km

All-single-mode-fiber

All-few-mode fiber

1 dBMPI

16 17 18 19 20 21 22 23 24 25 26 272

3

4

5

6

7

8

9


Q (

dB)

4060 km

All-single-mode-fiberAll-few-mode fiberHybrid

16 17 18 19 20 21 22 23 24 25 26 272

3

4

5

6

7

8

9


Q (

dB)

4060 km

2030 km

All-single-mode-fiberAll-few-mode fiberHybrid

MPI_FMF -10.88 dB

MPI_Hybrid -14.69 dB

Optical Fiber 13.


Paths to higher submarine cable capacity

Paths to Higher Capacity

More λ’s in C band

C+L band EDFA

Use >8 FPs in the repeater

Vascade EX2000

Vascade EX3000

50km

80km

50km

80km

80 λ’s 15.5 17.1 16.3 17.9

100 λ’s 16.5 18.1 17.3 18.9

150 λ’s 18.2 19.8 19 20.6

• Only small additional power is needed (rel. to current 17-19 dBm)

• No change in design

• Possible to support 300 λs for C+L band transmission

• May require re-designed repeaters

• May need more/re-design power feed equipment

• Use of all 8 FPs is supported by an original design

• No change in design

Use all 8 FPs in the repeater

• May require more repeaters or re-designed repeaters

• Requires more copper to reduce resistance; more expensive cable

Will likely be developed in parallel

Optical Fiber 14.


Challenge

Objective

Expanding Terrestrial Backbone NetworksTwo scenarios operators are facing today

Greenfield

Building fiber where it isn’t

available today

Difficult environments

Legacy

Meeting increased demand

Aging infrastructure

Cost (CapEx, OpEx), Reliability, Speed to Rollout, Complexity,…..

Optical Fiber 15.


The carriers that are building greenfield long haul networks are doing so for various reasons

Routing DiversityAccess to new

markets

Support for national broadband plans

Backhaul for wireless build-outs

Optical Fiber 16.


Greenfield long haul builds are also often driven by non-telco operators, a few examples

DefenseOil and Gas

Science Border SecurityElectric Utilities

Optical Fiber 17.


Many of the new long haul builds are going through challenging terrain

Optical Fiber 18.


Locating and powering remote amplifier or repeater sites can be problematic

Sites require power for equipment and cooling

Many may not even be accessible 365days a year

Optical Fiber 19.


How much can an intermediate amplifier site cost?

Amplifier Site Requirement Estimated Costs (low) Estimated Costs (high)

Site construction costs (acquisition, preparations, security, etc.)

$100k $250k+

Controlled Environment Vault (CEV)

$30k $150k

AC Power Construction ($22k/km)

$10k $500k

DC Power Back-up (Batteries, Fuel Cells, Generator, etc.)

$150k $300k

OPEX ( Fuel, Service, Labor, Road Access, Site Maintenance, Security etc.)

$36k/year $200k/year

Total of first year costs $326k $1.4M

Additionally, reliability and accessibility can be issues in some regions

Optical Fiber 20.


Minimizing intermediate amplifier or regenerator sites can be a key consideration

Example: China’s State Grid Project through the Himalayas• Average Elevation 5,000m,

temperatures as low as -55C• Span distances > 300km

One very long span Or several long spans

Example: TIM Brasil through Amazon region• Over 2000km of OPGW• 13 Spans longer 100km, 5 Spans

longer than 200km

Optical Fiber 21.


Technologies are enabling more robust and flexible network design, and reducing the need for intermediate amplifier sites

Better ElectronicsModulation and FEC

Increase in optical link length

adopting next generation FEC

1st gen

FEC

2nd gen

FEC

2nd gen

FEC

3rd gen

FEC

3rd gen

FEC

4th? gen

FEC

Coherent Detection

Advanced Amplification

EDFA

High Power EDFA

+ Counter Propagating Raman

+ Co-Propagating Raman

+ ROPA

+ Dual ROPA

Ultra Low Attenuation and Large Aeff Fibers

“Low-Loss”

“Ultra-Low-Loss”

“Ultra-Low-Loss” +

Large Aeff

Optical Fiber 22.


0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.15 0.155 0.16 0.165 0.17 0.175 0.18

Cu

mm

ula

tiv

e P

rob

ab

lity

(%

)

Attenuation at 1550 nm (dB/km)

Cable

Fiber

Post dead-line paper at OFC 2014 makes use of coherent detection, Raman amplification and advanced fiber to set new 100G distance record

• Cable: 8.3 km Altos loose tube 204 cable on a 0.9m diameter spool • Optical Fiber: Vascade EX2000 with Aeff=112 µm2

– Median attenuation improved after cabling from 0.161 dB/km to 0.159 dB/km, max attenuation 0.173 dB/km

• Span: 556.7 km, total loss 90.2 dB, spliced attenuation 0.162 dB/km

Source: Xia, Chang, Ten, et al OFC 2014 Th5A.7

Optical Fiber 23.


Trial set-up: Utilized Dual Raman and ROPA

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

(a)

ROPA (B)

ROPA (F)

p

P’

133.7 km

556.7 km for 1 x 100G transmission and 523 km for 4 x 100G transmission

Passive repeater

Source: Xia, Chang, Ten, et al OFC 2014 Th5A.7

Vascade® EX2000 fiber

Optical Fiber 24.


We have demonstrated two record results at OFC 2015 with two external partners: ASN and Xtera

Optical Fiber 25.


Challenge

Objective

Expanding Backbone NetworksTwo scenarios operators are facing today

Greenfield

Building fiber where it isn’t

available today

Difficult environments

Legacy

Meeting increased demand

Aging infrastructure

Cost (CapEx, OpEx), Reliability, Speed to Rollout, Complexity,…..

Optical Fiber 26.


We have recently investigated maximum reach and achievable capacity over a DT network when using three types of fibers

• Transparent network (no intermediate regeneration)

• 504km is the maximum distance between two adjacent cities

Optical Fiber 27.


Fiber rankings in terms of transmission reach:1) Vascade® EX2000; 2) SMF-28® ULL; 3) Legacy fiber

• System parameters:– EDFA noise figure: 5dB– Span length: 80km– WDM channels: 150– Cable drum length: 4km– Splice loss: 0.05 dB– 32Gbaud (6.25dB FEC threshold)– Polarization multiplexing– End-of-life cable margin: 3dB/100km– Additional Q margin: 3dB

Legacy fiber Corning®

SMF-28® ULL

Corning®

Vascade® EX2000

Attenuation

(dB/km)0.25 0.165 0.159

Aeff (µm2) 82 82 112

n2 (m2/W) 2.3 x 10-20 2.1 x 10-20 2.1 x 10-20

Dispersion

(ps/nm/km)17 17 20.3

Gaussian noise analytical model; implementation penalty neglected

Optical Fiber 28.


Legacy fiber Extra reach enabled by SMF-28 ULL fiber

Legacy fiber can support 24% of routes at 200G

SMF-28 ULL covers 96% of routes; Vascade EX2000 covers all

Transparent networks make the distribution of distances wider –SMF-28 ULL fiber covers 96% of links at 200G with 80km spans

Extra reach enabled by

Vascade EX2000 fiber

Optical Fiber 29.


Building cost effectively as a large incumbent carrier – Things to think about

Take advantage of existing duct

Take advantage of lower-cost installation techniques

Convergence

Build as a Consortium

Thank you

Optical Fiber 31.


• In traditional single-mode fibers the light propagates in the fundamental mode, which is the only mode supported in the fiber

• In quasi-single mode fibers, the light is “forced” on a fundamental mode

Tx Rx

Tx Rx

How does a Quasi-Single Mode Fiber work?

Optical Fiber 32.


Roadmap for terrestrial system capacity growth:Smarter Networking, FEC and more Raman

2015 20252020

Raman Amplifiers

100G MSA

50/100/150/200G

50-200G; with finer tuning

FEC Improvements

Smart Networking

The carriers are split on those who deploy 100G now, or wait until adaptive-rate transponders become available

SE

Rea

ch (

km) 50G

100G

200G

3 6

150G

1.5 4.5SE

Rea

ch (

km) 50G

100G

200G

3 6

150G

1.5 4.5

Optical Fiber 33.


WW Long-Haul Market

90% of the New Long Haul Routes are being build outside North America and Europe

Source: CRU

~90% of the LH market is in emerging

regions

Optical Fiber 34.


In 2009 traditional Telecoms started loosing their dominance as primary carriers of Internet traffic, CDNs gained share

• CDNs became as influential as traditional carriers as telecom equipment buyers and defining technology direction

2009 University of Minnesota Atlas Observatory study

Optical Fiber 35.


Adaptive modulation techniques optimize today’s wireless networks and tomorrow’s fiber networks

The same concept is now being used in transmission over optical fiber – providing similar benefits

Speed (Mb/s)

Distance from cell tower (km)

Optical Fiber 36.


Variable-rate transponder uses adaptive modulation to enable elastic optical networks

Source: “Extending software defined network principles to include optical transport”, Verizon, IEEE Communications Magazine, March 2013

• 1 bit per symbol

• 2 bits per symbol



Incr

easi

ng S

E a

nd r

equi

red

OS

NR

BPSK

QPSK

8 QAM

16 QAM

cHigher modulation density

provides more bits per channel…

…but shortens the reach

Optical Fiber 37.


SMF-28® ULL and Vascade® EX2000 fibers also maximize achievable capacity for a given reach

QPSK 8-QAM 16-QAMPM-BPSK 32-QAM 64-QAM

Spectral efficiency, b/s/Hz

Maximum reach, km

Legacy fiber

SMF-28® ULL fiber

50G

Modulation:

Bit-rate: 100G 150G 200G 250G 300G

50% Vascade® EX2000 fiber

100%Extra 50%

3x

30%

Fiber Technology Trends for Next Generation Networks

Technology

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