High-Capacity Optical Networks With or Without Repeaters

Transcription

High-Capacity Optical Networks
With or Without Repeaters
Massimo Leo
Fiberoptikk Conference – Trondheim, Norway – 2-3 November 2015
© 2015 Xtera Communications, Inc. Proprietary & Confidential
1
The Data Center Opportunity in Norway
•
Cool climate and supply of cold
water  natural free cooling
•
Green power  Europe’s largest
producer of hydroelectric power
•
Surplus of renewable, tax-friendly
energy  lower costs
Opportunity for High Capacity and
Cost-per-Byte efficiency
2
Interconnecting Data Centers
DCI Market Trends
Source: Ovum 2015
Cloud and video are driving
data center builds
...and changing how networks are
constructed
DCI is the fastest growing
application for optical
networking
…DCI revenues grew 16.2% in 2014,
surpassing US$2.5bn, and projected to
grow at 10.5% CAGR
Most Content Providers are
securing fiber and building
their own networks
…as opposed to lease managed capacity
services from Carriers
3
Optical Networking Requirements for DCI and
International Connectivity
• High Capacity
– Maximize # of Tbps per Fiber
• Long Spans & Reach
– Minimize # of Intermediate Sites
– Reach out Longer Distances
• Low Latency
– Minimize # of Regeneration Sites
• Over Land & Under Sea
– Converged Terrestrial and
Submarine Optical Solutions
– Cost-efficient also across Short
Distances
4
Driver for Longer Single-Span Optical Systems
City A
Optical
Equipment
Optical
Equipment
Optical
Equipment
Innovative Unrepeatered Offering
PoP or DC
Cable Landing Station
Submarine cable
Terrestrial extension
City B
Optical
Equipment
Confidential – Xtera Communications, Inc. Proprietary
5
Direct PoP-to-PoP: Better Cost/Bit and Latency
Removing CLS Equipment
Optical
Equipment
City A
PoP or DC
Submarine cable
Terrestrial extension
BMH
BMH
City B
Optical
Equipment
Requires Superior Optical Technology
Innovative Unrepeatered Offering
Confidential – Xtera Communications, Inc. Proprietary
6
Maximizing Reach in Single-Span Systems
Tool Kit (1/3)

1. Fiber
– Lower attenuation fiber is always better  Ultra low-loss (G.652B, G.654B)
– Type  Fibers with large effective area tolerant to higher launched power
2. Electro-Optics Silicon
–
–
–
–
–
–
–
Line rate 100G, 150G, 200G, 300G, 400G and Beyond
Modulation format
Pulse shaping
Channel density and flex grid
Wavelength of transmission (fiber attenuation lower in L-band)
Detection (Coherent)
Forward Error Correction (Soft-Decision FEC)
3. Power Management
– Launched power; power in the line fiber
– Non-linearities mitigation


7
Maximizing Reach in Single Span Systems
Tool Kit (2/3)

4. Raman amplification
– Results from the interaction of an optical radiation (“pump”) with molecular
vibrations of the glass
– In any fiber types
– The more pump power the more gain
– Raman gain improves with lower
fiber attenuation (larger Leff)
Thus the NF and OSNR improvements
due to Raman will be larger in lower
attenuation fiber at the same
Raman pump power.
Raman gain (a.u.)
• Maximum gain at a shift of ~ 100 nm in the 1550 nm window
6
Pump
5
4
~ 100 nm
3
2
1
0
0
6


Resulting gain

12
18
24
30
36
42
48
Frequency shift (THz)

8
Raman Amplification
Power Profile along the Span (Backward Raman)
Fiber attenuation
Gain from backward
Raman pumping
266 km (61.2 dB); G.652D
15x100G
9
Raman Amplification
Power Profile along the Span (BWD & FWD Raman)
Gain from
forward
Raman
pumping
Fiber attenuation
Gain from backward
Raman pumping
288 km (65.5 dB); G.652D
15x100G
10
Maximizing Reach in Single Span Systems
Tool Kit (Cont’d)

5. Remote Optically Pumped Amplifier (ROPA)
– Passive sub-system, made up of a few optical components (housed in an
enclosure jointed to the cable) and pumped from one end of the span
(typically, receive end)
– Basically, performs the function of a mid-span EDFA
Erbium
doped
Signal fibre
in
Signal
out
Optical pump (from the
receive terminal)
– More pump power allows ROPA to be located further away from the terminals


~ 100 km

ROPA



11
Example of ROPA Enclosure for Subsea
Applications
Courtesy of Nexans
12
ROPA
Power Profile along the Span
Gain from
forward
Raman
pumping
Fiber attenuation
Gain
from
ROPA
373 km (76.1 dB); G.652B
Gain from backward
Raman pumping
107 km
ROPA
15x100G
13
Per channel power (dBm)
410 km (68.2 dB), 150 x 100G Unrepeatered
Transmission over G.654B Fiber
150 wavelengths
Gain from
backward
Raman
pumping
Fiber attenuation
Gain from
forward
Raman
pumping
Gain
from
ROPA
Transmission distance (km)
LRA (Discrete Raman amplifier)
289 km
LRA
121 km
ROPA
<Pout> = -2.8 dBm/ch
<OSNR> = 14.2 dB
Power (dBm)
Power (dBm)
0
-5
-10
5
0
0
-5
-10
-15
-15
-20
1535
1545 1555 1565 1575
Wavelength (nm)
1585
1595
-25
1525
-5
-10
-15
-20
-25
1525
5
Power (dBm)
5
-20
1535
1545 1555 1565 1575
Wavelength (nm)
1585
1595
-25
1525
1535
1545 1555 1565 1575
Wavelength (nm)
1585
1595
14
557 km (90 dB), 1 x 100G Unrepeatered
Transmission over G.654B Fiber
Corning® Vascade® EX2000 (G.654B), Aeff=112 mm2
•
Backward AND forward ROPAs – No use of extra fiber for pumping
Per channel power (dBm)
•
1 wavelength
Gain from
forward
Raman
pumping
Fiber attenuation
Gain
from
ROPA
Gain
from
ROPA
Gain from
backward
Raman
pumping
Transmission distance (km)
133 km
291 km
133 km
EDFA
ROPA
Forward
Raman
pumping
ROPA
Direction of
transmission
Backward
Raman
pumping
15
Most Recent Unrepeatered Results by Xtera
16
Raman for Multi-Span Applications
100G across Ultra-Long Spans over 2,266km OPGW
43 km
13.9 dB
278 km
63.1 dB
237 km
53.8 dB
142 km
34.6 dB
138 km
33.1 dB
ROADM
ILA
ROADM
ILA
ILA
Manaus
TIM
Manaus
Rod Lexuga
Silves
Terra Santa
Oriximiná
ROADM
43 km
13.9 dB
239 km
54.2 dB
ILA
ILA
ILA
Villa
Camburão
110 km
27.2 dB
235 km
53.5 dB
ROADM
Jurupari
ROADM
183 km
46.1 dB
Macapá
TIM
ILA
Macapá Sub
141 km
33.9 dB
Gopa
Tucuruí
Core
amplifier
Backward span
extension module
ILA
Laranjal do Jari
157 km
37.2 dB
Pacaja
ILA
Xingu
Forward span
extension module
91 km
23.8 dB
229 km
52.8 dB
ILA
Vitória do Xingu
G.652
fiber span
17
Why Using Wideband Raman Amplification in
Subsea Repeaters?
Google (ECOC – Sept 2014): Spectrum efficiency (bit/s/Hz) is now close to the
Shannon limit… Need to either:
1. Increase the # of fibers: too expensive
2. Increase the # of cores: too long term (10+ year) solution
3. Expand the spectrum width (without compromising the reach)
Option #3 is the one developed and field-proven by Xtera
18
Mastering Raman Amplification
3x Capacity
240 channels
150 channels
80 channels
2x Reach
More Capacity in Long Haul applications for 100G, 400G and Beyond
19
World-first Raman Repeater for Subsea Cable Systems
• 50% more optical bandwidth and longer spans
• Down to 8,000m, up to 12kV
• Titanium alloy: as strong as steel, yet 45% lighter
• Very compact for easy seabed burial through plough
20
Xtera Product Portfolio
Maximizing Capacity and Reach
For Optical Networks
Partners Ecosystem
In-House Developed
Nu-Wave Optima
NMS
Single DWDM & SLTE
Vessel
Repeater
Cable
ROPA
Branching Unit
Submerged Equipment
Turnkey Solutions
24
Unified Terrestrial and Submarine Networks
Xtera Portfolio and Application Example
Terrestrial fiber
Subsea fiber
Regional
Repeatered
DWDM optical
systems
Unrepeatered
Repeater
Transoceanic
Repeatered
Branching Unit
25
Conclusion
• Field-proven Raman optical unrepeatered
transport technologies can offer today:
– Up to 600+ km unrepeatered reach
– Up to 15 Tbit/s capacity per fiber pair
• Optical unrepeatered transport technologies
can be applied to multi-span links:
– Key to minimize the number of intermediate sites
– Long-span capabilities required for OPGW cable in
utilities power grids
• Raman-based optical subsea repeaters are
now in commercial service for wider spectrum
and/or longer repeater spacing.
26
Maximizing Network Capacity, Reach and Value
Over land, under sea, worldwide
27

High-Capacity Optical Networks With or Without Repeaters

Transcription

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