latest trends in fiber communicatio
TRANSCRIPT
Dr.V.P. Sudeep KumarDr.V.P. Sudeep Kumar
Sr. Sub Divisional EngineerSr. Sub Divisional Engineer
RTTC, BSNLRTTC, BSNL
Latest Trends in Optical Communication
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What is meant by bandwidth?
Why infra red light is used in optical fibers?
Why the bandwidth is so high in Optical Communication?
Some Questions…
Gigabit,Terabit,Petabit,exabit zettabit and yottabit……………..
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Basically- E/O and O/E
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Fiber optic communication system
Transmitter
Receiver
Optical Fibre
Light ray trapped in the core of the fibre
Electrical input signal
Electrical output signal
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• 1960 - Invention of laser - Schawlow and Townes
• 1965- Optical fiber by Charles Kao and Hockam
• 1970- Practical optical fiber by Maurer et.al
• 1983- Optical links used for Internet(TCP/IP)
• 1993- WWW emerged
• 2000- Data traffic exceeded that of voice
• 2005- Tera bit - communication systems.
Rise and Rise of optical fibers
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Dr.Kao
Lighting the Future
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Fiber is not enough- huge BW is needed?
• Dramatic increase of Internet traffic
– data overcomes voice
– Data tsunami
• Impact on the network– data-centric
• access
• Core
2000 2004 20080
5
year
traffi
c (a
rb.
un
.)
voice
data
Data networks
BusHub
SwitchToken Ring
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Increasing bandwidth Options in fiber
Same bit rate, more fibers
Faster Electronics(TDM) Higher bit rate, same fiber
More Fibers(FDM)
WDM
Same fiber & bit rate, more s
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Single Wavelength Vs Multi wavelength.
MultiwavelengthTransmitter
MUX
MultiwavelengthReceiver
DMX
opticaltransmitter
opticalreceiver
optical fibreoptical fibre + –
TDM
WDM
Limits to 10 Gbps…?
4x 10 Gbps…?
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DWDM-How it works
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Evolution of DWDM
Late 1990’s
1996DWDM
Early1990’s
Narrowband WDM
1980’sWideband WDM
16+ channels 100~200 GHz spacing
2~8 channels200~400 GHz spacing
2 channels1310nm, 1550nm
64+ channels25~50 GHz spacing
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DWDM-How it works
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DWDM -analogy
►STM-1STM-1 155Mb155Mb
►STM-4STM-4 622Mb622Mb
►STM-16STM-16 2.5Gb2.5Gb
►STM-64STM-64 10Gb10Gb
►STM-128STM-128 40Gb40Gb
►STM-64STM-6410Gb10Gb
►STM-16STM-162.5Gb2.5Gb
►STM-16STM-162.5Gb2.5Gb
►STM-16STM-162.5Gb2.5Gb
►STM-64STM-6410Gb10Gb
►STM-16STM-162.5Gb2.5Gb
►STM-16STM-162.5Gb2.5Gb
►STM-16STM-162.5Gb2.5Gb
Maximum=40Gb
Maximum
40Gb*8=
320Gbps
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DWDM- Transmission Bands
Band Wavelength (nm)
820 - 900
1260 – 1360
“New Band” 1360 – 1460
S-Band 1460 – 1530
C-Band 1530 – 1565
L-Band 1565 – 1625
U-Band 1625 – 1675
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Centre Frequency Wavelength Centre Frequency Wavelength (THz) (nm) (THz) (nm)
195.9 1530.33 : :195.8 1531.12 : :195.7 1531.90 : :195.6 1532.68 192.6 1556.55195.5 1533.47 192.5 1557.36195.4 1534.25 192.4 1558.17195.3 1535.04 192.3 1558.98195.2 1535.82 192.2 1559.79 : : 192.1 1560.61 : : 192.0 1561.42 : : 191.9 1562.23 : : 191.8 1563.05 : : 191.7 1563.86
N.B. Channel Spacing 100 GHz (0.1 THz) or 0.8 nm.
ITU-T Frequency Grid For WDM
For DWDM - G.692 Rec.
Terminal A Terminal B
Post-Amp
Pre-Amp
Line Amplifiers
MUX
DEMUX
TransponderInterfaces
TransponderInterfaces
DirectConnections
DirectConnections
MultiWavelength(DWDM)
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1
2 ..
32
1
:
2
32
Multiplexers
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Multiplexing (DWDM) ?
At Ingress: Multiple Optical signals of differing wavelengthsare combined to form a single optical signal.
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Multiplexing
Mu
ltip
lex
er 1, 2, 3, 4
1
2
3
4
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Optical Multiplexing
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Demultiplexing (DWDM)
At Egress: A single Optical signals is refracted to separate multiple Optical signals of differing wavelengths.
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Demultiplexing
De
mu
ltip
lex
er
1, 2, 3, 4
1
2
3
4
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Bidirectional Wavelength Division Multiplexing(CWDM)
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A
B
WDMMux/Demux
AA
B
Receiver
Transmitter
Local Transceiver
WDMMux/Demux
B
A
B
Receiver
Transmitter
Distant TransceiverFibre
Significant savings possible with so called bi-directional transmission using WDM
This is called "full-duplex" transmission
Individual wavelengths used for each direction
Linking two locations will involve only one fibres, two WDM mux/demuxs and two transceivers
Bi-directional using WDM
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Coarse Wavelength Division Multiplexing(CWDM)
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WDM with wider channel spacing (typical 20 nm)
More cost effective than DWDM
Driven by: Cost-conscious telecommunications environment
Need to better utilize existing infrastructure
Main deployment is foreseen on: Single mode fibres meeting ITU Rec. G.652.
Metro networks
CWDM
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1270 1290 1310 1330 1350 1370
1390 1410 1430 1450 1470 1490
1510 1530 1550 1570 1590 1610
ITU-T G.694 defines wavelength grids for CWDM Applications
G.694 defines a wavelength grid with 20 nm channel spacing: Total source wavelength variation of the order of ± 6-7 nm is assumed Guard-band equal to one third of the minimum channel spacing is sufficient.
Hence 20 nm chosen
18 wavelengths between 1270 nm and 1610 nm.
ITUCWDM
Grid(nm)
CWDM Wavelength Grid: G.694
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Ultra Dense Wavelength Division Multiplexing(UDWDM)
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Trend is toward smaller channel spacings, to incease the channel count
ITU channel spacings are 0.4 nm, 0.8 nm and 1.6 nm (50, 100 and 200 GHz)
Also spacings of 0.2 nm (25 GHz) and even 0.1 nm (12.5 GHz)
Requires laser sources with excellent long term wavelength stability, better than 10 pm
One target is to allow more channels in the C-band without other upgrades
Wavelength in nm
Ultra Dense Channel Spacing
0.2 nm
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Optical adding and DroppingOADM
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Transponder
DWDM Multiplexer
Power Amp
Line Amp
Receive Preamp
200 km
DWDM DeMultiplexe
r
Each wavelength still behaves as if it has it own "virtual fibre"
Wavelengths can be added and dropped as required at some intermediate location
ReceiversAdd/Drop Mux/Demux
Optical fibre
Optical Add-Drop
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An Optical Add-Drop Multiplexer allow access to individual DWDM signals without conversion back to an electronic domain
In the example below visible colours are used to mimic DWDM wavelengths Wavelengths 1,3 and 4 enter the OADM Wavelengths 1 and 4 pass through Wavelength 3 (blue) is dropped to a customer Wavelengths 2 (green) and a new signal on 3 (blue) are added Downstream signal has wavelengths 1,2,3 and 4
Wavelengths 1 2 3 4
1 2 3 41 2 3 4
Wavelengths 1 2 3 4
OADM
Dropped Wavelength(s) Added Wavelength(s)
Optical Add-Drop Multiplexer
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Optical Cross connectsOXC
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Need reconfigurable OADM, allows change to the added and dropped wavelengths
OADM becomes an OXC (Optical Cross-Connect)
Large number of DWDM wavelengths possible means a large number of ports
Needs to be remotely configurable, intelligent
Should be non-blocking, any combination of dropped/added possible
In addition, insertion loss, physical size, polarization effects, and switching times are critical considerations.
Source: Master 7_7
Incoming DWDM signal
Dropped Wavelength Fibre Ports
Outgoing DWDM signal
Added Wavelength Fibre Ports
OXC
Optical Cross-Connect (OXC)
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Key component-Fiber Grating
• In an FBG, a periodic variation in refractive index is induced along the core of an optical fiber.
• The refractive index variation is made by exposing the fiber to the UV-light with a fixed interference pattern.
Glass core
Glass cladding Plastic jacket Periodic refraction index change(Gratings)
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Optical Amplifiers-EDFA and Raman
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Erbium Doped Fiber Amplifier
“Simple” device consisting of four parts:
• Erbium-doped fiber
• An optical pump (to invert the population).
• A coupler,an isolator to cut off backpropagating noise
Isolator Coupler Isolator
Erbium-DopedFiber (10–50m)
PumpLaserPumpLaser
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Erbium Doped Fiber Amplifier
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ERBIUM ELECTRONSIN FUNDAMENTAL STATE
PUMP PHOTON980 nm
Optical Amplifier:Principle
1480
980
820
540
670
Ground state
Metastablestate
1550 nm
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Optical Amplifiers:Principle
PUMP PHOTON980 nm
ENERGY ABSORPTION
ERBIUM ELECTRONSIN EXCITED STATE
ERBIUM ELECTRONSIN FUNDAMENTAL STATE
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Optical Amplifiers:Principle
PUMP PHOTON980 nm
TRANSITION METASTABLE STATEEXCITEDSTATE
FUNDAMENTAL STATE
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PUMP PHOTON 980 nm
TRANSITIONMETASTABLE STATE
TRA
NS
ITION
ASE Photons1550 nm
Optical Amplifiers:Principle
FUNDAMENTAL STATE
EXCITEDSTATE
FUNDAMENTAL STATE
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PUMP PHOTON 980 nm
TRANSITION
METASTABLE STATE
SIGNAL PHOTON 1550 nm
STIMULATEDPHOTON1550 nm
Optical Amplifiers:Principle
FUNDAMENTAL STATEFUNDAMENTAL STATE
EXCITEDSTATE
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Optical Amplifiers:Multi-wavelength Amplification
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EDFA-Commercial
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Optical Amplifiers - Applications
• In line amplifier-30-70 km-To increase transmission link
• Pre-amplifier- Low noise-To improve receiver sensitivity
• Booster amplifier- 17 dBm- TV
• LAN booster amplifier
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Raman Amplifier
Transmission fiber
1550 nm signal(s)
Cladding pumped fiber laser
1450/ 1550 nm WDM
1453 nm pump
ErAmplifier
Raman fiber laser
Transmission fiber
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Trends in Optical amplifier
• Rare earth-Doped Fiber AmplifiersErbium-Doped Fiber Amplifiers (EDFA) : C, L-BandThulium-Doped Fiber Amplifiers (TDFA) : S-BandPraseodymium-Doped Fiber Amplifiers (PDFA) : O-Band
• Fiber Raman AmplifiersDiscrete Raman AmplifiersDistributed Raman Amplifiers (DRA)
• Semiconductor Optical Amplifiers (SOA)conventional SOA
• Hybrid Amplification
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ClientOLTE
For Example :
SDH STM-16 / SONET OC-48
2.5 Gb/s on 1 fiber of 70 km
Use of Optical Amplifiers
ClientOLTE
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TX RX
OAOA
For Example :
SDH STM-16 / SONET OC-48
Link with 1 transmission Optical Amplifier (OA)
Point to Point Link
2.5 Gb/s on 1 fiber of 100 km
Use of Optical Amplifiers
ClientOLTE
ClientOLTE
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OAOA
TX RX
OAOA
For Example :
SDH STM-16 / SONET OC-48
Link with 1 transmission OA + 1 receiver OA
Point to Point Link
2.5 Gb/s on 1 fibre of 250 km
Use of Optical Amplifiers
ClientOLTE
ClientOLTE
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OAOA
TX RX
For Example :
SDH STM-16 / SONET OC-48
Link with 1 transmission OA + 1 receiver OA + With line OA
Point to Point Link
2.5 Gb/s on 1 fiber of 500- 600 km
Use of Optical Amplifiers
ClientOLTE
ClientOLTE
OAOAOAOA
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TDM Solutions for 600 Kms
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
SDH SDH3R 3R 3R 3R 3R 3R 3R 3R 3R 3R 3R
32 Clients => 64 Fibers + 704 3R SDH / SONET Regenerators
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WDM Solution for 600 Kms
SDH SDH
SDH SDH
SDH SDH
SDH SDH
SDH SDH
SDH SDH
OM /
OA
OA /
OD
OA OA OA
32 Clients => 2 Fibers + 5 Optical Amplifiers
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Manufacturer Channel Count Total Capacity
Lucent 82 3.28 Terabits/sec
Alcatel 128 5.12 Terabits/sec
NEC 160 6.4 Terabits/sec
Siemens 176 7.04 Terabits/sec
Alcatel 256 10.2 Terabits/sec
NEC 273 10.9 Terabits/sec
Recent DWDM capacity records
Exploiting the Full Capacity of Optical Fibre
NTT-1046 lamda 25 Tbps
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Fiber Communication systems
Intra 2Km
Short 15 Km
Long LR1 40 Km
Long LR2 80Km
Very 120 Km
Ultra 160 Km
Long Up to 600 km
Very 600-1000 Km
Ultra 1000-2000 Km
Terrestrial Submarine
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A1 Nodes - 5
A2+A3 Nodes - 9
A4 Nodes - 10
B1 + B2 Nodes - 47
Jullundar
Jaipur
Pune
Ahmedabad
Indore
Lucknow
Patna
Noida
Kolkata
ChennaiBanglore
Mumbai
Ernakulam
Hyderabad
Chandigarh
Manglore
SiSi
Bhubneshwar
SiSi
Ranchi
Allahabad
SiSi
Coimbtore
Madurai
Trichy
Palghat
Trivandrum
Trichur
Kalikat
SiSi
Vijaywada
Rajmundary
Vizag
Tirupati
Durgapur
Siliguri
Dimapur
SiSi
Guwahati
Kalyan
Panjim
Aurangabad
Kolhapur
Nashik
SiSi
Nagpur
Bhopal
Gwalior
Mehsana
Ambala Faridabad Gurgaon
Meerut
Agra
Dehradun
Ludhiana
Ferozpur
Shimla
Amritsar
SiSi
SiSi
Ajmer Jodhpur
MysoreHubli
Jamshedpur
Surat
Vadodara
Rajkot
Jabalpur
Shilong
Ghaziabad Noida
Varanasi Kanpur
Pondicherry
Belgaum
SiSi
Raipur
SiSi
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Undersea Optical communication
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The first decade of subsea fiber optics
–1986; First international subsea optical cable between U.K. and Belgium
–1988: TAT-8 becomes the first transoceanic optical cable–1992: TAT-9 and TAT-10 with 565mb capacity each –1993: TAT-11 with 2x565mb, the first gigabit level transoceanic cable!
–1994: Cantat-3 with 5gig!–1998: Atlantic Crossing 1 with 840 gig design capacity!–Then came the terabit years
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Ten years later (end 2008)
• Approx. 25 Terabit capacity under the atlantic • 13 Terabit circling South America• 23 Terabit under the Pacific• 33Tb East and North-East Asia• 2.5Tb Europe-Asia; another 14.3Tb for 2009-2010
(IMEWE, EIG, MENA)• Only 0.355 Terabit circling the west part of the
African continent, nothing on the east-side but that will change considerably over the next three years starting with Seacom later this year.
ALCATEL OALC4 - 17mm Cable
Cables
• Do not regenerate, amplify
• Erbium-doped fiber amplifier
• Well adapted to WDM
• Direct monitoring
3 m
Multiple channels in a fiber
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Under sea cable
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Cable routes Survey
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Under sea
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Under sea cable
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Under Sea communication
• More than 650000km
• Production 150000 km/yr
• More than 140 cable laying ships
• Domestic and international
• Depth 1000m to 2000m at a burial depth of 3m
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SEA-ME-WE 3
JAPAN
Okinawa
S. KOREA
Keoje
UK
CHINA
Shanghai
Shantou
TAIWAN
Taipei
Toucheng
Fangshan
HONG KONG
Deep Water Bay
PHILIPPINES
Batangas
VIET NAM
Danang
THAILAND
Satun
MALAYSIA
Mersing SINGAPORE
Tuss
Tungku
INDONESIA
Jakarta
Medan
INDIA
Cochin
Munbai
MYANMAR
Pyayyypon
PAKISTANOMAN
U.A.E.
DJIBOUTI
SAUDI ARABIA
TURKEY
CYPRUS
GREECE
FRANCE
PORTUGAL
MORACCO
ITALY
Penang
20 Gbps (STM-128) 2.5 Gbps x 4 Wavelengths x 2 Fiber PairsSubmarine Cable Network
Branch Unit
Type: Consortium
EGYPT
DWDM-China-US
US
Bandon, OR
San Luis Obispo, CA
CHINA
Chongming
Shantou
GUAM
80 Gbps / 2XSTM-2562.5 Gbps x 8 Wavelengths x 4 Fiber Pairs
JAPAN
Chikura
Okinawa
S. KOREA
Pusan
TAIWAN
Fangshan
Active
16,000 Route miles
Type: Consortium
DWDM PC - 1
US
Harbour Pointe, WA
JAPAN
Ajigaura
Initial 160 Gbps capacity, 2.5 Gbps (STM-16) x 8 Wavelengths x 4 fiber pairs(Upgradeable to 640 Gbps using DWDM technology)
Shima
Grover Beach, CA
Type: Private (Global Crossing)
640 Gbp/s SDH Ring Design
In Service
November 2000
12,600 Route miles
Japan-US
JAPAN
Kita-Ibaraki
Maruyama
HAWAII
Makaha Beach, Oahu
US
Manchester, CA
Shima
Moro Bay / San Luis Obispo, CA
640 Gbp/s SDH Ring10 Gbps x16 Wavelengths x 4 Fiber Pairs
12,00 Route miles
Southern Cross
Branch Unit
USA
Nedonna, OR
San Luis Obispo, CA
HAWAII
Kahe Point
Spencer Beach
NEW ZEALAND
Takapuna
Whenuapal
AUSTRALIA
Belrose, Sidney
Rosebery, Sidney
FIJI
Suva
160 Gbp/s SDH Ring Design
80 Gbp/s SDH Ring Design
Backhaul & cable sys interface: STM-1
November 2000
November 2000
November 2000
January 2001
FLAG Pacific-1
Type: Private (FLAG Telecom)
JAPAN
Misaki
Chikura
HAWAII
Honolulu
US
Washington
ALASKA
Aleutians
CANADA
Vancouver Is.
Bay Area - North
Bay Area - South
Tokyo / Yokahama Loop
22,000 Route miles
Supplier is Alcatel
10 Gbps x 64 Wavelengths x 8 Fiber Pairs
Repeatered Repeatered
Repeatered
Repeatered
Repeatered
Vancouver / Seattle Loop
San Francisco / Los Angeles
Loop
S. Korea
Pusan
TAIWAN
Toucheua
MALAYSIA
Kuan Tan
JAPAN
Kitaibaraki
Chikura
CHINA
Shanghai
Shantou
SINGAPORE
Katoug
HONG KONG
LantauPHILIPINES
Batangas
2.56 Tbp/s SDH Ring Design
10 Gbps x 64 Wavelengths x 4 Fiber Pairs
ASIA PAC CABLE NETWORK 2___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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Questions ???Questions ???