Tera-Bit Optical Submarine Networks - Meeting the Market's Capacity Demands at Lowest Overall Cost Tera-Bit Optical Submarine Networks - Meeting the Market's

Tera-Bit Optical Submarine Networks -Tera-Bit Optical Submarine Networks -

Meeting the Market's Capacity DemandsMeeting the Market's Capacity Demands

at Lowest Overall Costat Lowest Overall Cost

Tera-Bit Optical Submarine Networks -Tera-Bit Optical Submarine Networks -

Meeting the Market's Capacity DemandsMeeting the Market's Capacity Demands

at Lowest Overall Costat Lowest Overall Cost

Katsutoshi Tamura, Katsutoshi Tamura, General ManagerGeneral ManagerSubmarine Networks Business DivisionSubmarine Networks Business DivisionInternational Telecommunications Business GroupInternational Telecommunications Business GroupFujitsu LimitedFujitsu Limited

Tatsuo Matsumoto, Tatsuo Matsumoto, Senior Director Senior DirectorSubmarine Telecommunications Engineering DivisionSubmarine Telecommunications Engineering DivisionTransport Systems GroupTransport Systems GroupFujitsu LimitedFujitsu Limited

Colin Anderson, Colin Anderson, Manager Business Development Manager Business DevelopmentSubmarine Networks Sales & MarketingSubmarine Networks Sales & MarketingInternational Telecommunications Business GroupInternational Telecommunications Business GroupFujitsu LimitedFujitsu Limited

PTC2000 Hawaii: A New Vision for the 21 st CenturyPTC2000 Hawaii: A New Vision for the 21 st CenturySession T.1.4.1 Tuesday 1 February 2000Session T.1.4.1 Tuesday 1 February 2000

File: Tera-Bit Submarine Networks.ppt Issue 2.2 28 January 2000

Copyright - Fujitsu Proprietary Slide 2

PTC2000: Tera-Bit Optical Submarine Networks - Meeting the Market's Demand at the Lowest Overall Cost

IntroductionIntroduction

Demand for international traffic continues driven by the Internet

Vendors strive to meet capacity and cost demands

Fortunately technology has enabled both capacity increases and cost reductions

Focus of this paper is “cost” rather than “capacity”

What have been the price implications of the technologies recently deployed ?

What will be the likely impacts of the next generation of'enabling technologies' on price as well as capacity ?

Which technologies will be best for the future submarine networks ?




Typical WDM Optical Submarine Network ConfigurationTypical WDM Optical Submarine Network Configuration

Terminal Station EquipmentWDM: N channels of traffic ontoN wavelengths on a single fiber

Terminal Station Equipment

WDM Evolution:8 x 2.5 Gb/s ... 16 x 2.5 Gb/s … 16 x 10 Gb/s ... 32 x 10 Gb/s …64 x 10 Gb/s ... 128 x 10 Gb/s ... ? 8 x 40 Gb/s ... 16 x 40 Gb/s ... ?

Up to 200 Cascaded Optical Amplifiers

Span between Terminals: 500 km ~ 10,000 km(span between “optical - electrical” & “optical - electrical” conversion)

40 ~ 80 km between Repeaters




Key Enabling TechnologiesKey Enabling Technologies

Erbium Doped Fiber Optical Amplifer

Study mid 1960's Practical reality in laboratories mid-1980's Practical in commercial networks early 1990's Slow start perhaps, but a dramatic impact in latter part of 1990's

Dense DWM Optical Devices

Wavelength-Locked Lasers Tunable lasers Passive optical devices (filters, multiplexers, etc...) etc




History of WDM Optical Submarine NetworksHistory of WDM Optical Submarine Networks

1995: 1 wave of 2.5 Gb/s or 5.0 Gb/s

1998: 8 waves x 2.5 Gb/s or 16 waves x 2.5 Gb/s

1999 / 2000: 32 waves x 10 Gb/s being contracted

Systems with 64 waves x 10 Gb/s will be commercialisedin the next two years

Foreseeable future: 128 x 10 Gb/s using C-Band and L-Band

N x 40 Gb/s systems will follow

Currently up to 4 fiber pairs in submerged plant

6 and 8 fiber pair systems by 2002




Figure 1: Transmission Capacity per Optical FiberFigure 1: Transmission Capacity per Optical Fiber (8 x 2.5 Gb/s ~ 32 x 40 Gb/s) (8 x 2.5 Gb/s ~ 32 x 40 Gb/s)

0 Gb/s

200 Gb/s

400 Gb/s

600 Gb/s

800 Gb/s

1,000 Gb/s

1,200 Gb/s

1,400 Gb/s

2.5x8x2 2.5x8x6 2.5x16x42.5x16x82.5x32x22.5x32x6 10x16x410x16x810x32x210x32x6 10x64x410x64x810x128x210x128x640x8x4 40x8x8 40x16x240x16x6 40x32x440x32x8

S yste m T yp e (l in e ra te x w a ve s x fib e r p a i rs)

1,000 G b/s = 1 Tb/s

Nomenclature: "10 x 32 x 4" means

"10 Gb/s x 32 waves x 4 fiber pairs"

1,000 Gb/s = 1.0 Tb/s

N x 10 Gb/s N x 40 Gb/s




Figure 2: Transmission Capacity per Cable System Figure 2: Transmission Capacity per Cable System (8 x 2.5 Gb/s ~ 32 x 40 Gb/s)(8 x 2.5 Gb/s ~ 32 x 40 Gb/s)

Figure 2: Transmission Capacity per Submarine Cable(8 x 2.5 Gb/s ~ 32 x 40 Gb/s, 1 ~ 8 fiber pairs)

0 Gb/s

2,000 Gb/s

4,000 Gb/s

6,000 Gb/s

8,000 Gb/s

10,000 Gb/s

12,000 Gb/s

2.5x8x22.5x8x6 2.5x16x42.5x16x82.5x32x22.5x32x610x16x410x16x810x32x210x32x6 10x64x410x64x810x128x210x128x6

40x8x4 40x8x8 40x16x240x16x6 40x32x440x32x8


1,000 G b/s = 1 Tb/s

10,000 G b/s = 10 Tb/s

Nomenclature: "10 x 32 x 4" means

"10 Gb/s x 32 waves x 4 fiber pairs"

10,000 Gb/s = 10 Tb/s




History of Submarine Cable CapacityHistory of Submarine Cable Capacity

Period from 1989 to 1999

eg: TPC 3 = 2 x 280 Mb/s Optical Regenerator System Japan - US Cable = 16 x 10 Gb/s x 4 fiber pairs

Greatest increase in capacity with introduction of WDM technology

Extrapolation to Year 2010 ?

For example using the 'rule-of-thumb' growth rate predictionof "2 times per year" from 1999 base ?




Figure 3: Submarine Cable Capacity verses Time, 1989 ~ 2010 ? Figure 3: Submarine Cable Capacity verses Time, 1989 ~ 2010 ?

Prediction of 2x /yr

from 1999

TPC-3 : 1x280M b/s

TPC-4: 1x560M b/s

TPC-5: 1x5Gx2fp

SEA-M E-WE-3: 8x2.5Gx2fp

CHINA-US: 8x2.5Gx4fp

SOUTHERN CROSS: 16x2.5Gx4fp

JAPAN-US: 16x10Gx4fp

64x10Gx6fp

32x10Gx6fp

32x10Gx4fp

128x10Gx6fp

0 Gb/s

1 Gb/s

10 Gb/s

100 Gb/s

1,000 Gb/s

10,000 Gb/s

100,000 Gb/s

1985 1990 1995 2000 2005 2010

= 1 Tb/s

= 100 Tb/s

= 10 Tb/s

Figure 3: Submarine Cable Capacity vs Time

1,200 m

120 m

12 m

1,200,000

120,000

Equivalent number ofvoice circuits (uncompressed)




Price History of Submarine Cable SystemsPrice History of Submarine Cable Systems

Breakdown of price has been changing as capacity has increased

In past, large percentage of total price was in submerged plant, and capacity was fixed from initial deployment

Increasing number of waves of WDM has led to increased percentage of the total price is terminal equipment

< 8 x 2.5 Gb/s: submerged 50 ~ 65 %; terminal 8 ~ 25 % 32 x 10 Gb/s: submerged 20 ~ 40 %; terminal 50 ~ 60 % (fully equipped) (major variation is with SLTE - SLTE span) Future terminal equipment approaching 70 % fully equipped? Also an increase in floor space for terminal equipment




Price per Unit Capacity ComparisonPrice per Unit Capacity Comparison

Price per unit of traffic capacity has dramatically decreased("price-per-bit" or "price-per-STM-1" etc)

One of the factors stimulating cable deployment

Internet provided traffic demand (pull), and technology has reduced the cost per bit faster than market decreases in selling price per bit

For example 8 x 2.5 Gb/s to 16 x 2.5 Gb/s ~ 40 % decrease in cost per STM-1 due to technology 16 x 2.5 Gb/s to 16 x 10 Gb/s: ~ 65 % decrease in cost per STM-1 32 wave systems: perhaps 30 % ~ 35 % lower than 16 x 10 Gb/s ? Full information in Figure 4 (2,000 km) and Figure 5 (8,000 km)




Figure 4: Overall Price per STM-1 over 2,000 km Submarine LinkFigure 4: Overall Price per STM-1 over 2,000 km Submarine Link

Figure 4: Overall Price per STM-1 over 2,000 km8 ~ 32 x 2.5 Gb/s & 16 ~ 32 x 10 Gb/s, 2 ~ 8 fiber pairs

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

2.5x8x12.5x8x22.5x8x32.5x8x42.5x8x62.5x8x8 2.5x16x12.5x16x22.5x16x32.5x16x42.5x16x62.5x16x8 2.5x32x12.5x32x22.5x32x32.5x32x42.5x32x62.5x32x8 10x16x110x16x210x16x310x16x410x16x610x16x8 10x32x110x32x210x32x310x32x410x32x610x32x8


1, 2, 3, 4, ... 6, ... 8 pairs




Figure 5: Overall Price per STM-1 over 8,000 km Submarine LinkFigure 5: Overall Price per STM-1 over 8,000 km Submarine Link

Figure 5: Overall Price per STM-1 over 8,000 km8 ~ 32 x 2.5 Gb/s & 16 ~ 32 x 10 Gb/s, 2 ~ 8 fiber pairs

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

2.5x8x2 2.5x8x4 2.5x8x6 2.5x8x8 2.5x16x22.5x16x42.5x16x62.5x16x8 2.5x32x22.5x32x42.5x32x62.5x32x8 10x16x210x16x410x16x610x16x8 10x32x210x32x410x32x610x32x8


2, 4, 6, 8 pairs




Technology History, Current & Future Technology TrendsTechnology History, Current & Future Technology Trends

Optical Amplifier Bandwidth & Amplitude Response

Traditionally used optical C-band (centered on 1,550 nm) L-Band becoming available (new EDFA) Bandwidth and flatness improvements Terrestrial systems announced in mid-1999:

80 x 10 Gb/s in C-Band + 90 x 10 Gb/s in L-Band (1.7 Tb/s per fiber) For submarine systems: C-Band = 26 nm, L-Band = 30 nm useable?

Number of WDM Channels, Bit Rate, Channel Spacing

WDM wave spacing: 1.6nm 0.8 nm 0.4 nm 0.3 nm possible ? 0.2 nm unlikely ? 0.4 nm allows > 64 waves in C-Band plus > 64 waves in L-Band




Optical Fiber Spectrum & Types of Optical AmplifierOptical Fiber Spectrum & Types of Optical Amplifier

1,450nm 1,490nm 1,530nm 1,570nm 1,610nm 1,650nm

S+ Band S Band C Band L Band L+ Band

RFA

TDFA EDTFA

GS-EDFAEDFAErbium DopedFiber Amplifier

Gain-ShiftedErbium DopedFiber Amplifier

Tellurite-BasedErbium DopedFiber Amplifier

Thulium DopedFlouride-BasedFiber Amplifier

Raman Fiber Amplifier

Total ~ 200 nm: 500 ~ 1,000 waves ?

80 nm: ~ 200 waves ?

40 nm

1,550nm 1,580nm

Potential of Optical Fiber: perhaps 250 waves x 100 Gb/s = 25,000 Gb/s = 25 Tb/s ?





Number of WDM Channels, Bit Rate, Channel Spacing (cont)

As channel numbers increase, total power must be kept constant and so power per wave decreases

Repeaters need to be closer together (price and noise increase) Eventually, increasing the number of repeaters to give closer

repeater spacing gives worse performance (noise increase overwhelms other gains). Limit of the technology is reached.

Optical Amplifier Pumping Technologies

Traditionally 1,480 nm pumping lasers (cost & reliability) 980 nm lasers now available for lower noise in pre-amplifier stages combination of 980 nm and 1,480 nm in 'forward' and 'reverse'

pumping directions currently optimum




Forward & Reverse Pumping Using 980 nm & 1,480 nm Pumping LasersForward & Reverse Pumping Using 980 nm & 1,480 nm Pumping Lasers

Erbium Aluminum Doped Optical FiberL = 10 ~ 80m, Er ~ 500 ppm = 0.05 %

980nm PumpLaser Diode

20:1 Coupler

1,480nm PumpLaser Diode

Rear ModulatorReflector / Isolator

PIN

Input Output

Long PeriodFiber Grating

SV Monitor & Control Circuiit

LPG

PIN

20:1 Coupler

Input LevelMonitorPhoto-Diode

Output LevelMonitorPhoto-Diode

DC Input Power: 9 V 0.87 A ~ 8 W typ

3dBCoupler

WDM MUX

3dBCoupler

980nm Pumping 1,480nm Pumping





Optical Amplifier Pumping & Output Power

Use of two 980 nm Pump Lasers and two 1,480 nm Pump Lasers is now not only cost effective, but further benefits reliability against hardware failures of lasers

Fiber non-linearities (not the amplifiers in the repeaters) now limit the maximum output power

Optical Amplifier Noise Figure

Current schemes have reduced noise figure of the amplifiers from 6.7 dB to around 5.5 dB resulting in increased spans between repeaters and lower overall costs





Non-Linear Effects / Optical Fiber Effective Area

Non-Zero DSF has relatively small "effective area" compared to regular "Single Mode Fiber" (SMF)

Concentration of the light energy causes non-linear effects in the optical fiber

Several "Large Effective Area" optical fibers now available "Large Effective Area Fiber" is itself more expensive, but used in the

first half of the span it allows higher output powers (without non-linear distortions)

Hence increase repeater spacing (overall cost savings)





Dispersion Compensation

Non-Zero DSF (or Large Effective Area optical fiber) + positive dispersion fiber, to give overall average zero dispersion

But only at one wavelength!Imperfect correction at other wavelengths

Increasing numbers of waves of WDM mean increased band-widths, and the current dispersion compensation schemes are not perfect over large band-widths.





Amplitude-Slope Compensation

Amplitude-slope is introduced by the fiber itself as well as the amplifiers

Current technologies only partially compensate

Active Gain-Slope Correction

New technology - remotely provisionable over the lifetime of the system. Reduce initial margins, and hence repeater cost savings




Effect of Gain Slope in the NetworkEffect of Gain Slope in the Network

0.00

10.00

20.00

30.00

-20.00 -10.00 0.00 10.00 20.00

0.00

10.00

20.00

30.00

-20.00 -10.00 0.00 10.00 20.00

0.00

10.00

20.00

30.00

-20.00 -10.00 0.00 10.00 20.00

Noise Floor

Noise Floor

Degraded Optical SNR(Signal to Noise Ratio)

Degraded SNR

Input Signaleg: 32 x 10 Gb/s

After Transmission (Case 1)

After Transmission (Case 2)

Before Transmission

Uniform Signal to Noise Ratio (SNR)




Advances in Terminal EquipmentAdvances in Terminal Equipment

Modulation Techniques

Traditionally Non-Return-to-Zero coding (NRZ) was preferred Recently significant advances in modulation hardware devices have

meant that Return-to-Zero modulation coding is simpler and more cost effective for 10 Gb/s WDM systems

However other schemes (Optical Duo-Binary, etc) hold even further promise for 40 Gb/s systems (improved dispersion tolerance, etc)

Forward Error Correction

Redundant information to allow error correction at the far end Bit rate is increased, but improvements in SNR far outweigh this

penalty Currently 4 ~ 6 dB of improvement (7 % bit rate increase)





Forward Error Correction (cont)

Next generation "Super FEC" gives 7 ~ 10 dB of improvement(equivalent to > 4 x number of WDM waves)

Increased repeater spacing and significant cost savings Increased maximum spans

Dispersion Compensation

Reverse Dispersion Fibers (RDF or +D / -D) Improved technical performance as well as space savings at

terminal stations (less DCF)





Tunable Lasers

Big savings for customer in spares Savings for manufacturer in number of different component types Eventually multiple wavelength arrays - further cost savings

Floor Space Requirements

Dense WDM systems require increasing terminal station space Cable station space is a real cost to the customer Re-locate SLTE to Central Station? (pros & cons) Separate Cable termination & Power Feed (at shore station) from

SLTE (at intermediate site) Use optical-layer protection instead of SDH protection




Next Generation 40 Gb/s SystemsNext Generation 40 Gb/s Systems

Next logical choice for transmission rate after 10 Gb/s is 40 Gb/s

Many technical challenges (much more difficult than the migration 2.5 Gb/s 10 Gb/s)

Key issues include very high speed optical and electronic components severe effects of Chromatic Dispersion, Self-Phase Modulation (SPM), and

Polarisation Mode Dispersion (PMD) in the optical fiber when transmitting 40 Gb/s

To eventually be successful we know that 40 Gb/s systems will need to offer capacity increase at significantly reduced price per bit, as well as floor space savings

Past historical rule: “... 4 times the capacity for 2 ~ 3 timesthe price ...” ? Assumed in this paper.




Future Submarine Network Price TrendsFuture Submarine Network Price Trends

System prices modelled for spans of 2,000 km ('short-haul') and 8,000 km ('long-haul') as earlier discussed

In fact N x 40 Gb/s may be limited to less than 8,000 km for some time to come ... but we assumed that the hurdles will eventually be overcome

Current market prices used where items exist, and'best estimate' prices used for future technologies

Hypothetical study, but rational and hopefully useful




Figure 6: Overall Price per STM-1 over 2,000 km Submarine Link Figure 6: Overall Price per STM-1 over 2,000 km Submarine Link

Figure 6: Overall Price per STM-1 over 2,000 km16 ~ 128 x 10Gb/s & 8 ~ 32 x 40 Gb/s, 2 ~ 8 fiber pairs

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

10x16x110x16x310x16x6 10x32x210x32x410x32x810x64x110x64x310x64x6 10x128x210x128x410x128x840x8x1 40x8x3 40x8x6 40x16x240x16x440x16x840x32x140x32x340x32x6



1, 2, 3, 4, ... 6, ... 8 pairs




Figure 7: Overall Price per STM-1 over 8,000 km Submarine Link Figure 7: Overall Price per STM-1 over 8,000 km Submarine Link

Figure 7: Overall Price per STM-1 over 8,000 km16 ~ 128 x10 Gb/s & 8 ~ 32 x 40 Gb/s, 2 ~ 8 fiber pairs

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

10x16x210x16x410x16x610x16x8 10x32x210x32x410x32x610x32x8 10x64x210x64x410x64x610x64x8 10x128x210x128x410x128x610x128x840x8x240x8x440x8x640x8x8 40x16x240x16x440x16x640x16x8 40x32x240x32x440x32x640x32x8



2, 4, 6, 8 pairs




Price-per-Bit Comparison SummaryPrice-per-Bit Comparison Summary

64 x 10 Gb/s compared to 32 x 10 Gb/s(640 Gb/s per fiber pair cf 320 Gb/s per fiber pair) (2x)

Long-haul: approx 25% savings (20 ~ 30%) Short-haul: approx 23% savings (17 ~ 30 %)

128 x 10 Gb/s compared to 64 x 10 Gb/s(1,280 Gb/s per fiber pair cf 640 Gb/s per fiber pair) (2x)

Long-haul: 10 ~ 15% increase in price per bit (but capacity doubled) Short-haul: approx same price per bit (but capacity doubled)

8 x 40 Gb/s compared to 32 x 10 Gb/s(320 Gb/s per fiber pair in both cases) (1x)

15 ~ 20 % savings approx (short-haul or long-haul)




Price-per-Bit Comparison SummaryPrice-per-Bit Comparison Summary

16 x 40 Gb/s compared to 64 x 10 Gb/s(640 Gb/s per fiber pair in both cases) (1x)

~ 25 % savings approx (short-haul or long-haul)

32 x 40 Gb/s compared to 64 x 10 Gb/s(1,280 Gb/s per fiber pair cf 640 Gb/s per fiber pair) (2x)

~ 50 % savings approx (short-haul or long-haul)

Please correct yourhard-copy printout




Comparison of 40 Gb/s to 10 Gb/sComparison of 40 Gb/s to 10 Gb/s

64 x 10 Gb/s systems are economical compared to 32 x 10 Gb/s, and will continue to provide good solutions for up to 5 Tb/s per cable (64 x 10Gb/s x 8 fp) at low cost-per-bit

Next step of 128 x 10 Gb/s may not be so attractive from point of view of ‘price per bit’ or floor space requirements

When 40 Gb/s systems become available commercially they will compete well at 320 Gb/s per fiber and above, and will offer best solutions for 320 Gb/s to 10 Tb/s per cable (32 x 40G x 8 fp)

40 Gb/s systems can be expected to much reduce floor space requirements at terminal stations of very high capacity systems




Future Network Architectures & Protection SchemesFuture Network Architectures & Protection Schemes

The above analysis does not include SDH Multiplex orNetwork protection Equipment

Combined SDH (SIE, MUX & NPE) typically represents approx15 % of the total network price, fully equipped (& much less for initial sub-equipped configurations; perhaps 3 ~ 7 % ?)

Other drivers are acting - SONET / SDH are excellent for voice networks but somewhat inefficient for data-centric andIP-centric networks: ‘IP over WDM’ vs ‘IP over SDH’

Separate the MUX / SDH SIE requirement from the NPE requirement ?




Future Network Architectures & Protection SchemesFuture Network Architectures & Protection Schemes

Full function Network Protection can be provided by new optical layer NPE equipment without the need for any protocol dependence (SDH, etc), and with lower power consumption and floor space requirements than for SDH

Price is already less than for SDH NPE in some configurations

Increased use of optical layer NPE in terrestrial networks will soon see further price reductions in optical switches and optical NPE's




Summary & ConclusionsSummary & Conclusions

We have tried to identify the impacts of recent technology developments on both capacity, price, & price-per-bit for submarine cable networks

In future there seem to be several identifiable promising new key technologies, including 40 Gb/s transmission, which will be able to be exploited to give further capacity increases and at the same time give price-per-bit decreases

The era of ‘Terabit’ Submarine Cable Networks is certainly already with us - and the same kind of technology developments which made those networks feasible seem likely to be able to continue to offer the future solutions which the market-place demands, and at affordable prices

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Tera-Bit Optical Submarine Networks - Meeting the Market's Capacity Demands at Lowest Overall Cost Tera-Bit Optical Submarine Networks - Meeting the Market's