fiber technology trends for next generation networks
TRANSCRIPT
Christopher ToweryCorning Optical Communications
May 28th 2015
IV Towards Terabit per Second Optical NetworkingInternational Workshop on Trends in Optical Technologies
Optical Fiber 2.
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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.
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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.
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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.
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What are the CDN’s saying about submarine networks?-- More capacity…..
Optical Fiber 6.
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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.
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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.
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• 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.
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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.
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Technology – Ultra-Large Aeff
OFC 2015 post-deadline paper demonstrates record SE over Trans-Atlantic distance using Quasi-SMF fiber
Optical Fiber 11.
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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.
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-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
Received OSNR @ 0.1 nm (dB)
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
Received OSNR @ 0.1 nm (dB)
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
Received OSNR @ 0.1 nm (dB)
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.
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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.
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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.
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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.
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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.
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Many of the new long haul builds are going through challenging terrain
Optical Fiber 18.
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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.
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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.
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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.
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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.
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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.
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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.
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We have demonstrated two record results at OFC 2015 with two external partners: ASN and Xtera
Optical Fiber 25.
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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.
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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.
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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.
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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.
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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.
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• 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.
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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.
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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.
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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.
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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.
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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
• 3 bits per symbol
• 4 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.
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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%