The document provides an overview and agenda for a presentation on advances in Dense Wavelength Division Multiplexing (DWDM). It begins with definitions of DWDM and how it works by combining multiple optical transmitters onto an optical fiber using different wavelengths. It then covers optical fiber types and properties, linear and non-linear effects that impact transmission over fiber including attenuation, chromatic dispersion, optical signal-to-noise ratio, and solutions to mitigate these effects like amplifiers, dispersion compensation, and forward error correction. Finally, it reviews common DWDM components like transmitters, receivers, mux/demux filters, optical add/drop multiplexers, and reconfigurable optical add/drop multiplexers.
3. ď§ Introduction â What is DWDM?
ď§ Optical Fiber
ď§ Linear/Non-linear Effects and
Solutions
ď§ DWDM Components and Software
ď§ Intro to OTN
ď§ Increasing Capacity, Flexibility and
Reach in DWDM
ď§ Next Generation DWDM/Optics
Agenda
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Wavelength Division Multiplexing
⢠DWDM systems use optical devices to combine the output of several optical
transmitters
Optical
fiber pair
TX
Optical
transmitters
Optical
receivers
TX
TX
TX
RX
RX
RX
RX
Transmission
DWDM devices
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ITU-T Grid
Frequency
(THz)
Wavelength
(nm)
1528.77 nm 1578.23 nm
0.4 nm spacing
1552.52 nm
(Center channel)
196.2 THz 190.1 THz193.1 THz
(Center channel)
50 GHz spacing
ITU wavelengths = lambdas = channels center around 1550 nm (193 THz)
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Fiber Geometry and Dimensions
⢠The core carries the light signals
⢠The refractive index difference
between core & cladding confines
the light to the core
⢠The coating protects the glass
Coating
250 microns
Cladding
125 microns
Core
SMF 8 microns
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Communication Wavelengths in the InfraRed
ď§ 850 nm Multimode
ď§ 1310 nm Singlemode
ď§ C-band:1550 nm Singlemode
ď§ L-band: 1625 nm Singlemode
UltraViolet InfraRed
850 nm 1310 nm 1550 nm 1625 nm
l
Wavelength: l (nanometers)
Frequency: ďŚ (terahertz)
C =ďŚ x l
Visible
Optical Spectrum
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ď§ Good for TDM at 1310 nm
ď§ OK for TDM at 1550 nm
ď§ OK for DWDM (With Dispersion Mgmt.
ď§ Good for CWDM (>8 wavelengths)
Extended Band
(G.652.C)
(suppressed attenuation in the
traditional water peak region)
ď§ OK for TDM at 1310 nm
ď§ Good for TDM at 1550 nm
ď§ Good for DWDM (C + L Bands)
NZDSF
(G.655)
ď§ OK for TDM at 1310 nm
ď§ Good for TDM at 1550 nm
ď§ Bad for DWDM (C-Band)
DSF
(G.653)
ď§ Good for TDM at 1310 nm
ď§ OK for TDM at 1550
ď§ OK for DWDM (With Dispersion Mgmt.)
SMF
(G.652)
Applications for the Different Fiber Types
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Transmission Impairments
⢠Attenuation
⢠Loss of Signal Strength
⢠Chromatic Dispersion (CD)
⢠Distortion of pulses
⢠Optical Signal to Noise
Ratio (OSNR)
⢠Effect of Noise in Transmission
800 900 1000 1100 1200 1300 1400 1500 1600
Wavelength (nm)
0.2
0.5
2.0
Loss (dB/km)
L-band:1565â1625nm
C-band:1530â1565nm
S-band:1460â1530nm
800 900 1000 1100 1200 1300 1400 1500 1600
Wavelength (nm)
0.2
0.5
2.0
Loss (dB/km)
L-band:1565â1625nm
C-band:1530â1565nm
S-band:1460â1530nm
Time Slot
10Gb/s
2.5Gb/s Fiber
Fiber
Time Slot
10Gb/s
2.5Gb/s Fiber
Fiber
S+N
N
S+N
N
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Attenuation
⢠With enough attenuation, a light pulse may not be detected by an optical
receiver
Insertion loss (dB)
Attenuation (dB)
Distance (km)
Optical device
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Fiber Attenuation (Loss) Characteristic
800 900 1000 1100 1200 1300 1400 1500 1600
OH- Absorption Peaks in
Actual Fiber Attenuation Curve
Wavelength in Nanometers (nm)
0.2 dB/Km
0.5 dB/Km
2.0 dB/Km
Loss(dB)/km vs. Wavelength
S-band:1460â1530nm
L-band:1565â1625nm
C-band:1530â1565nm
OH: Hydroxyl ion absorption is the absorption in optical fibers of electromagnetic waves,
due to the presence of trapped hydroxyl ions remaining from water as a contaminant.
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Laser Output Power and
Receiver Sensitivity and dBm
⢠Fiber loss expressed in dB but transmitter/receiver power is expressed in dBm
⢠This is why both the transmitter output power and the receiver sensitivity is
expressed in dBm:
PowerdBm=10log(PmW/1mW)
dB and dBm are additive, hence the simplification
Example:
⢠Powerdbm = 10log(2mW/1mW)=3dBm
⢠Powerdbm = 10log(1mW/1mW)=0dBm
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ď§ Gain expressed by ratio: Pout/Pin
ď§ Gain measured conveniently in dB: 10 log10 Pout/Pin
ď§ If the power is doubled by an amplifier, this is +3 dB
AmpPin Pout
Gain and Decibels (dB)
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Attenuation: Optical Budget
Optical Budget is affected by:
⢠Fiber attenuation
⢠Splices
⢠Patch Panels/Connectors
⢠Optical components (filters, amplifiers, etc.)
⢠Bends in fiber
⢠Contamination (dirt/oil on connectors)
Basic Optical Budget = Tx Output Power â Rx Input Sensitivity
Pout = +6 dBm R = -30 dBm
Budget = 36 dB
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Signal
Input
980 or 1480 nm
Pump Laser
Erbium
Doped
Fiber
Amplified
Signal
Output
Isolator
WDM Coupler for
pump and signal
Isolator
Basic EDFA
configuration
Attenuation Solution: EDFA
⢠Erbium doped fiber amplifies optical signals through stimulated emission using
980nm and 1480nm pump lasers
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Chromatic Dispersion (CD)
⢠Total dispersion is a function of the length of fiber and itâs dispersion factor
⢠Limits transmission distance for 10G and above wavelengths
⢠Can be compensated by using negative dispersion fiber or electronically through
modulation schemes
Bit 1 Bit 2 Bit 1 Bit 2Bit 1 Bit 2Bit 1 Bit 2 Bit 1 Bit 2
The Optical Pulse tends to Spread as it propagates down the fiber
generating Inter-Symbol-Interference (ISI)
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DCUs use fiber with
chromatic dispersion of
opposite sign/slope and of
suitable length to bring the
average dispersion of the
link close to zero.
Solution: Dispersion Compensating Unit
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Optical Signal-to-Noise Ratio (OSNR)
⢠OSNR is a measure of the ratio of signal level to the level of system noise
⢠As OSNR decreases, possible errors increase
⢠OSNR is measured in decibels (dB)
⢠EDFAs are the source of noise
Signal level dBm)
Noise level (dBm)
Signal level
OSNR = -----------------
Noise level
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Optical Signal Detection
⢠Across a fiber span, optical signals encounter attenuation, dispersion and
increased noise levels at amplifiers.
⢠Each of these factors causes bit detection errors at the receiver.
Distance (km)
Transmitting
end
Receiving
end
Low attenuation
Low dispersion
High OSNR
High attenuation
High dispersion
Low OSNR
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Example: Link Design with Line Amplifiers
10G Xenpak spec: Tx: +3 to -1dBm, Rx min: -21dBm (0ps/nm)
CD tolerance: +1600ps/nm @ 2dB penalty
OSNR min: 16dB (0.5nm resolution)
-1dBm +2dBm
0ps/nm
Time
Domain
Wavelength
Domain
OSNR: 18dB Rx:
-9dBm
Meets receiver minimum
OSNR and power
requirement
+2dBm/ch
TX RX
Tx: -1dBm min
Mux
Demux
DCU
-1600
ps/nm25dB 25dB
DCU
-1600
ps/nm
+2dBm/ch-23dBm/ch -23dBm/ch
OSNR= 21dB
Noise
OSNR= 18dB
Noise
OSNR= 35dB
Noise
-23dBm
1600ps/nm
+2dBm
0ps/nm
-23dBm
1600ps/nm
+2dBm
0ps/nm
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OSNR Solution #1
Raman Amplifier
⢠Stimulated Raman Scattering creates the Gain
⢠Reduces the effective span loss and increases noise performance
⢠Gain is highly dependent on quality of fiber
⢠Gain Spectrum ~ 40nm with a single pump
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Log
(BER)
4 5 6 7 8 9 10 11 12 13 14 15
â15
â14
â13
â12
â11
â10
â9
â8
â7
â6
â5
â4
â3
â2
â1
0
S/N (dB)
Uncoded
No FEC
G.709
RS(255,239)
Raw Channel BER=1.5e-3
EFEC=8.4 dB
FEC=6.2 dB
OSNR Solution #2: Forward Error Correction
⢠FEC extends reach and design
flexibility, at âsilicon costâ
⢠G.709 (G.709 Annex A) standard
improves
OSNR tolerance by 6.2 dB (at 10â15
BER)
⢠Offers intrinsic performance
monitoring (error statistics)
⢠Higher gains (8.4dB) possible by
enhanced FEC (with same G.709
overhead â G.975.1 I.4)
⢠New SD-FEC provides 2dB more
coding gain
Benefit: FEC/EFEC Extends Reach and Offers 10â15 BER
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Non Linear Effects
⢠Polarization Mode
Dispersion (PMD)
⢠Caused by Non Linearity Of
Fiber Geometry
⢠Effective for Higher Bit rates (10G)
⢠Four Wave Mixing (FWM)
⢠Effects multi-channel systems
⢠Effects higher bit rates
⢠Self/Cross Phase Modulation
(SPM, XPM)
⢠Caused by high channel power
⢠Caused by channel interaction
Wavelength (nm)
-5
-10
-15
-20
-25
-30
-35
-40
1542 1543 1544 1545 1546 1547 1548
Power(dBm)
Wavelength (nm)
-5
-10
-15
-20
-25
-30
-35
-40
1542 1543 1544 1545 1546 1547 1548
Wavelength (nm)
-5
-10
-15
-20
-25
-30
-35
-40
1542 1543 1544 1545 1546 1547 1548
Power(dBm)
nx
ny
Ex
Ey
Pulse As it Enters the Fiber
Spreaded Pulse As
it Leaves the Fiber
nx
ny
Ex
Ey
Pulse As it Enters the Fiber
Spreaded Pulse As
it Leaves the Fiber
Power
SPMDistortion
Power
SPMDistortion
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Typical Components of DWDM Systems
⢠Optical transmitters and receivers
⢠DWDM mux/demux filters
⢠Optical add/drop multiplexers (OADMs)
⢠Reconfigurable OADM (ROADM)
⢠Optical amplifiers
⢠Transponders/Muxponders
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Optical Transmitter Block Diagram
Detects pulses of
electrical charge
⢠Power measured in watts (W)
⢠Amplitude measured in
volts (V)
Creates pulses of light
⢠Power measured in
decibel-milliwatts (dBm)
⢠Relative amplitude
measured in decibels (dB)
Electrical conductor
E-O
Optical fiber
1 11 01 11 0
Electrical-to-optical
(E-O)
conversion
+
-
dB
+
-
V+ -
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Optical Receiver Block Diagram
Detects pulses of light
⢠Power measured in
decibel-milliwatt (dBm)
⢠Relative amplitude
measured in decibels (dB)
Creates pulses of electrical charge
⢠Power measured in watts (W)
⢠Amplitude measured in volts (V)
Electrical conductor
O-E
Optical fiber
+ -
Optical-to-electrical (O-
E)
conversion1 11 0+
-
dB
1 11 0+
-
V
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DWDM Mux and Demux Filters Block Diagram
1
2
3
N
DWDM
fiber
N light pulses of different wavelengths
From N
transmitters
To N
receivers
1
2
3
N
Composite
signal
Multiplexer Demultiplexer
1, 2, âŚ.N
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OADM Block Diagram
New data stream,
same wavelength
Signsl 1 drop
OADM
one signal
Pass through pathOriginal
composite signal
New composite
signal
Drop path Add path
DWDM
fiber
Signal 2 add
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ROADM Architecture
Add
Wavelengths
Drop
Wavelengths
Pass-Through Wavelengths
Splitter
Add
WavelengthsSoftware
Controlled
32 Ch. DeMux
Pass-Through WavelengthsSplitter
l1
Network
Element
l3
Network
Element
Software Controlled Selectors â 32 Ch.
(Pass-through/Add/Block)
DWDM
Signal
Transponder
Module
West
East
DWDM
Signal
Drop
Wavelengths
drop block blockdrop
dropblock block drop
Software
Controlled
32 Ch. DeMux
Add
Pass
Add
Pass
Network
Element
Network
Element
Transponder
Module
Pass
Pass
Add
Add
Software Controlled Selectors â 32 Ch.
(Pass-through/Add/Block)
l1l3
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Optical Amplifer Block Diagram
⢠Unidirectional operation
⢠Extends the reach of a DWDM span
OA
DWDM
fiber
Attenuated input
composite signal
Amplified output
composite signal
Powerin Powerout
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Transponder Block Diagram
Optical fiber
Non-ITU-T
compliant wavelength
ITU-T
compliant wavelength
O-E-O
wavelength conversion
850, 1310, 1550 nm 15xx.xx nm
Transponder
Tx
Rx
G.709 Enabled
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Muxponder Block Diagram
Optical fibers
Multiple Non-ITU-T
Compliant Clients
ITU-T
compliant wavelength
Multiplexing and O-E-O
wavelength conversion
850, 1310, 1550 nm
15xx.xx nmTx
Rx
Muxponder
G.709 Enabled
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Pluggable Optics
1G/10G
SFP/SFP+
40G/100G
CFP2, CFP, CPAK and CXP
10G/40G/100G
QSFP+/QSFP-28
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DWDM System
OEOTx
Rx
Tx
Rx
OADM OAOA
Rx Tx
Transponder interface
OEO
Tx
Rx
Tx
Rx
Direct interface
To client devices
ClientClient
Mux and
demux
Mux and
demux
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Intelligent DWDM
⢠Modern systems compensate real-time
for variations in the network
⢠Gain Equalization
⢠Amplifier Control
⢠Automatic Node Setup
⢠Automatic Power Control
⢠WSON Restoration
⢠OTDR
⢠Connection Verification
⢠Allows for less truck rolls and
maintenance windows
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Why Per-Channel Optical Power Equalization
⢠For amplifiers to operate correctly, all channels must be equalized in power.
⢠If channel powers are not equal, more gain will go to the higher powered channels.
⢠Channel power is inherently unequal due to different insertion losses, different
paths (add path vs. express/pass-through), etc.
⢠Controlling the optical power of each channel in an optical network is required.
AMP
AMP
Optical Power Equalized Channels
Channels with Unequal Optical Power
OADM Without Power Equalization
Express Path
Add/Drop
Path
Why Per Channel Equalization
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Automatic Power Control
⢠Automatically corrects amplifier
power/gain for capacity change, ageing
effects, operating conditions
⢠Keep traffic working after network
failires
⢠Prevent BER due to
network degrade
⢠Keep constant either power or gain on
each amplifier
⢠No truck rolls
⢠No troubleshooting required
⢠No operation complexity
APC
No Human Intervention Required
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OTDR- NCS 2000
⢠NCS 2000 supports Node Controller Line Cards
(TNCS-O)
⢠Each TNCS-O Line Card supports 2x
OTDR/OSC ports
⢠1 OTDR per Degree with up to 4 Degrees per NCS
2015 chassis â Dedicated OTDR
⢠Digital â Bit Stream instead of High Power Optical
Pulse
⢠In Band â Take measurements directly @ 1518nm,
no extrapolations
⢠Bi-directional operation â Tests both fibers and both
directions of the fiber with a single device
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47. Š 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 47BRKOPT-2106
Aggregation Technology
OTN Drivers
⢠Sub-Lambda
Aggregation/Switching
⢠Adapt to DWDM
⢠Switch/Router Intfc
Mismatch to DWDM
⢠Transparency
⢠Timing
⢠Protocols (i.e. OSPF vs
ISIS)
⢠Sub-Lambda Protection
⢠Unnecessary when client
interface = DWDM Trunk
Source: Infonetics
OTN Only
Packet
Aggregation OTN
OTN / Packet
Optimized
Private Line
Private Line
Private Line
Private Line
Not yet
needed
Money
saved
Îť2Îť1 Îť2Îť1
Îť2
deferred
Îť1
Private Line
Private Line
Private Line
Private Line
Private Line
Private Line
Private Line
Private Line
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OTN â A Quick refresher
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Three Architectural Options for OTN
49BRKOPT-2106
Switched
G.709
(Digital OTN)
Static WDM
(Analog OTN)
Flexible
WDM
(Analog OTN)
Switched
G.709
(Digital OTN)
Dynamic
WDM
(Analog OTN)
Framed G.709
(Digital OTN)
A B C
ď G.709 provides all
dynamic capabilities
ď WDM for capacity only
ď G.709 provides dynamic
switching
ď WDM with reconfigurable
connections
ď G.709 provides framing
only
ď WDM for all dynamic
capabilities
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Traffic Grooming
NCS 2000 400G XPonder
400G XPonder
⢠OTN Aggregation
⢠SNC Protection
Cross Platform Remote for 4K
OTN Engine
Metro WDM Ring
400G-Xponder
400G-Xponder
400G-Xponder
400G-Xponder
400G OTN
XPonder
400G OTN
XPonder
400G OTN
XPonder
400G OTN
XPonder
X
N
F
Q
L B
D
H
10GE Services
200G
WDM
200G
WDM
200G
WDM
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100G and Beyond â Coherent Detection
Direct Detection
⢠Must correct for impairments in the physical domain (insert DCUâs)
⢠Forced to live with non-correctable impairments via network design (limit
distance, regenerate, adjust channel spacing)
⢠Dumb detection (OOK), no Digital Signal Processing, only FEC
Coherent Detection
⢠Moves impairment correction from the optical domain into the digital domain
⢠Allows for digital correction of impairments (powerful DSP) vs. physical correction of
impairments (DCUâs). Adds advanced FEC.
⢠Massive performance improvements over Direct Detection.
DD
CD
DD
DCU DCU DCU
Regen
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Flexible Modulation â Reach vs. Capacity
BPSK 28 GBaud 56 Gbps 50 Gbps 10,000 km
QPSK 32 GBaud 112 Gbps 100 Gbps 6,800 km
16-QAM 35 GBaud 224 Gbps 200 Gbps 1,200 km
Modulation Baud Rate Line Rate Payload Rate Distance
53BRKOPT-2106
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Traditionally DWDM capacity is limited by the
channel spacing imposed by the 50GHz ITU grid.
Rigid Spacing
Wasted Spectrum
Superchannel with Minimal Spacing
Efficient Spectrum Use
Tightly spaced Superchannels deliver ~30% increase in capacity
50 GHz ITU Grid âGridless or FlexSpectrumâ
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FLOW â Flexible Lightwave Orchestration of
Wavelengths(Flex Grid)
Media-Channel: Continuous spectrum allocated
from Source to Destination
Super-Channel: set of homogeneous optical
carrier(s) of the same type
Carrier: Optical Channel carrying a portion or all
of the client payload
By default one MCH shall be associated to each
SCH
Each MCH can be switched/routed independently
⢠The MCH has the information on Optical BW
allocated and the Path along the network
⢠The SCH has information on the channels
contained, and all the optical data
⢠Several MCHs can be aggregated to form a
MCH-GROUP.
⢠MCH-GROUP has the same Src/Dest/Path
and are managed as a single entity
Media-Channel
Group
Super-Channel
SCH1
Super-Channel
SCH2
Super-Channel
SCH3
Carriers Carriers
Carrier
Media-Channel
MCH2
Media-Channel
MCH3
Media-Channel
MCH1
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ROADM brought flexibility to DWDM networks.
Any wavelength. Anywhere.
But it was static flexibility.
Moves and changes required a truck roll.
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⌠because ROADM ports were
colored and directional.
Colored Add/Drop
Fixed port frequency assignment
One unique frequency per port
Directional Add/Drop
Physical add/drop port is tied to a
ROADM âdegreeâ
Due to these restrictions, a change in direction or frequency of an optical circuit
required a physical change (move interface to different port) at the endpoints.
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Colorless Add/Drop
No port-frequency assignment
Any frequency, any port
With Colorless plus Omni-Directional, the frequency and direction of the signal
can be changed, without requiring a change of ROADM add/drop port, therefore
no truckrolls, and henceâŚprogrammability!
Omni-Directional Add/Drop
Add/Drop ports can be routed
to/from any ROADM degree
Colorless and Omni-directional add/drop bring
touchless flexibility, and hence programmability, to
ROADM networks.
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Directional Add/Drop ROADMs
form a Contentionless node by
definition.
With Contentionless, N instances of a given wavelength (where N = the number
of line degrees in the ROADM node) can be add/dropped from a single device,
eliminating any restrictions on dynamic wavelength provisioning.
Contentionless add/drop allows
multiple instances of the same
frequency to A/D from one unit.
ButâŚColorless and Omni-directional introduce
wavelength contention at the add/drop stage. Need
a Contentionless architecture.
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Transmitter can tune its laserâs
frequency to any channel in the
ITU grid.
Tunable lasers work with colorless add/drop to enable touchless changes in the
frequency of an optical signal. Coherent receivers simplify the construction of
colorless and omni-directional ROADM nodes, by eliminating the need to de-
multiplex a signal down to the individual wavelength.
Receiver can select any channel
from of a composite (unfiltered)
signal.
Tunable lasers and coherent receivers are also key
enablers of the touchless programmable optical layer.
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But this touchless capability is of limited use without
intelligence.
Intelligence to find an optically feasible
route through the network.
The WSON Control Plane combines
GMPLS signaling with knowledge of
optical interface requirements and
channel impairments.
WSON
Embedded Optical
Intelligence
WSON enables automated, constraint-
based zero-planning wavelength setup,
which in turn enables advanced optical
layer features such as Optical Restoration.
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Dynamic Optical Restoration
Client
Colorless, Omni-Directional ROADM switches the path
Service is brought back up with the same Client and Optical interfaces, zero touches
Embedded WSON intelligence locates and verifies a new path and wavelength
Transponders re-tune to available wavelength
Fiber Cut!
animated slide
Client
ROADM Network
Transponder
Shelf
Transponder
Shelf
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64. Š 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public
OpenConfig data-model support ready
64BRKOPT-2106
Automation for Increased Visibility
65. Š 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public
⢠96 channels of 250G @ 24Tbps
⢠Solution upgradeable to high baud rate
line rates
⢠Smart licensing option available
⢠AES-256 encryption available
Point-to-Point Metro Optimized DWDM Transport Solution
⢠IOS-XR software for complete automation with
enhanced monitoring
⢠Local and network boot (iPXE and ZTP)
⢠Programmability with YANG model based APIs
⢠Headless mode for data plane resiliency
⢠LLDP, trunk trace, locator beacon and more
NCS 1001
Amplifiers + Protection + Channel Monitoring
IOS-XR
NCS 1002
8 250G MXP/TXPs
IOS-XR
15216 Mux-Demux
96 Channels
Passive
15216-MD-48-ODD=
15216-MD-48-EVEN=
65BRKOPT-2106
Transport for Cloud Networks
66. ď§ Introduction â What is DWDM?
ď§ Optical Fiber
ď§ Linear/Non-linear Effects and
Solutions
ď§ DWDM Components
ď§ DWDM Software
ď§ Intro to OTN
ď§ Increasing Capacity, Flexibility
and Reach in DWDM
Conclusion
68. Š 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public
Glossary
ďą Arrayed Waveguide (AWG)
ďą Automatic Node Setup (ANS)
ďą Automatic Power Control (APC)
ďą Chromatic Dispersion (CD)
ďą Cross Phase Modulation (XPM)
ďą Decibels (dB)
ďą Decibels-milliwatt (dBm)
ďą Dense Wavelength Division Multiplexing (DWDM)
ďą Dispersion Compensation Unit (DCU)
ďą Dispersion Shifted Fiber (DSF)
ďą Erbium Doped Fiber Amplifier (EDFA)
ďą Four-Wave Mixing (FWM)
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69. Š 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public
Glossary
ďąInternational Telecommunications Union (ITU)
ďąNon-Zero Dispersion Shifted Fiber (NZ-DSF)
ďąOptical Add Drop Multiplexer (OADM)
ďąOptical Signal to Noise Ratio (OSNR)
ďąOptical Supervisory Channel (OSC)
ďąOptical Supervisory Channel Module (OSCM)
ďąPolarization Mode Dispersion (PMD)
ďąReconfigurable Optical Add Drop Multiplexer (ROADM)
ďąSelf Phase Modulation (SPM)
ďąSingle Mode Fiber (SMF)
ďąVariable Optical Attenuator (VOA)
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71BRKOPT-2106