Company Confidential 1 Next Gen ROADMs “Less” is more: Colorless, Directionless, Contentionless,...
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Transcript of Company Confidential 1 Next Gen ROADMs “Less” is more: Colorless, Directionless, Contentionless,...
Company Confidential 1
Next Gen ROADMs“Less” is more:
Colorless, Directionless, Contentionless, Gridless
Krishna Bala, Ph.DExec VP WSS Group
ECOC 2010 Turin Italy
Company Confidential 2
Outline
• Next- Gen ROADM requirements• Architectural Choices• Implications for WSS devices
Company Confidential 3
Generations of ROADMs• 1st Gen ROADMs introduced the following features:
– Re-configurability in add/drop channels– However, these nodes were restricted to 2 directions
• 2nd Gen ROADMs introduced the following features:– Multi-degree capability (e.g. 4 or 8 directions per node)– However, these nodes are “colored” and “directional”
• 3rd Gen ROADMs will introduce more “Mesh” features:– Significant flexibility in provisioning and restoration– Colorless, Directionless, Contentionless and “Gridless”
(Flexible Spectrum actually)
Company Confidential 4
8x1 WSS
8x1 WSS
Passive
splitter
2nd Gen ROADM: 8 degree exampleColored and Directional
8x1 WSS
AWG
Colored: Each “chassis slot” is associated with specific “laser color”Directional: Each laser is associated with a specific direction
AWGAWG AWG AWG AWG
Rx
Tx
Add
/Dro
p
Degre
e 8
Degre
e 1
Degree 2
Company Confidential 5
West In
West Out
East In
East Out
North In North Out
Local Drop ports Local Add ports
• Colorless add/drop – No blocking in wavelength assignment on any Add/Drop
• Contentionless add/drop – No blocking inside ROADM due to wavelength collision
• Directionless add/drop – Full flexibility in routing to any direction
• Gridless - Dynamically allocate spectrum to each wavelength
ROADM Node
Requirements for 3rd Gen ROADMsNew Features for Mesh ROADMs/WSS
Company Confidential 6
West In
West Out
East In
East Out
North In North Out
Local Drop ports Local Add ports
• Colorless add/drop – No blocking in wavelength assignment on any Add/Drop
• Contentionless add/drop – No blocking inside ROADM due to wavelength collision
• Directionless add/drop – Full flexibility in routing to any direction
• Gridless - Dynamically allocate spectrum to each wavelength
ROADM Node
Requirements for 3rd Gen ROADMsNew Features for Mesh ROADMs/WSS
Of course, customers want ……. Costless As a supplier, we think ………….. Priceless
Company Confidential 7
3rd Gen ROADM: 8 degree exampleAdding Colorless Feature: Replace AWGs
Degre
e 8
8x1 WSS
8x1 WSS
Passive
splitter
Degre
e 1
Degree 28x1 WSS
AWG
Colored: Each “chassis slot” is associated with specific “laser color”Directional: Each laser is associated with a specific direction
AWGAWG AWG AWG AWG
Rx
Tx
Add
/Dro
p
Company Confidential 8
3rd Gen ROADM: 8 degree exampleColorless
8x1 WSS
8x1 WSS
Passive
splitter
8x1 WSS
Colorless: Each “chassis slot” can associate with any “laser color”Directional: Each laser is associated with a specific direction
AWGAWG AWG AWG AWG
Rx
1x24 WSS1x24 WSS1x24 WSS1x24 WSS1x24 WSS1x24 WSS
Degre
e 8
Degre
e 1
Degree 2
Add
/Dro
p
Tx
Colorless: Requires “Scalability” in WSS port count – Large port count
Company Confidential 9
3rd Gen ROADM: 8 degree exampleColorless AND Directionless
8x1 WSS
8x1 WSS
Passive
splitter
8x1 WSS
Degre
e 8
Degre
e 1
Degree 2
Add
/Dro
p
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
Passive splitter
Tx
Company Confidential 10
3rd Gen ROADM: 8 degree exampleColorless and Directionless: But, has Contention
8x1 WSS
8x1 WSS
Passive
splitter
8x1 WSS
Degre
e 8
Degre
e 1
Degree 2
Add
/Dro
p
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
Contention
Tx
Rx
Rx
Company Confidential 11
3rd Gen ROADM: 8 degree exampleColorless, Directionless, Contentionless
8x1 WSS
8x1 WSS
Passive
splitter
8x1 WSS
Degre
e 8
Degre
e 1
Degree 2
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
Tx
Rx
Rx
MxN WXCMxN WXC24x8 or 48x8 or ….24x8 or 48x8 or ….
MxN WXCMxN WXC8x24 or 8x48 or ….8x24 or 8x48 or ….
Contentionless: Requires “Scalability” in WSS ports – Large port counts
Company Confidential 12
3rd Gen ROADM: 8 degree exampleColorless, Directionless, Contentionless with “Grouping”
8x1 WSS
8x1 WSS
Passive
splitter
8x1 WSS
Degre
e 8
Degre
e 1
Degree 2
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
AWG AWG1x24 WSS1x24 WSS1x24 WSS
8x1 WSS
Tx
Rx
Rx
MxN WXCMxN WXC8x88x8
8x1 WSSMxN WXCMxN WXC
8x88x8
Company Confidential 13Xtellus Confidential - 13
1000 25 50 75-25-100 -75 -50 200125 150 175-125-200 -175 -150
Example: Add BW in 25GHz steps
3rd Gen ROADM:
Colorless, Directionless, Contentionless and “Gridless”
Dynamic/Flexible Spectrum Addition– Add BW in 25 Ghz steps– Allows future-proofing for higher speed transport
– E.g. 400 Gb/s and 1 Tb/s
Gridless: Requires Spectrum “Flexibility” in WSS
Company Confidential 14
WSS Roadmap for 3rd Gen ROADMs
• WSS must be SCALABLE– Large port counts
• 1x24 plus ports and beyond• MxN where M=8 and N=24 and beyond
• WSS must be FLEXBILE– Dynamic/Flexible Spectrum Alloction
• Other “Must Haves”– Fast switching speed: Fast mesh restoration– Green: Low power dissipation
Company Confidential 15
Conclusion
• 3rd Gen ROADMs require new features– Colorless, Directionless, Contentionless,
Gridless
• 3rd Gen WSS must support– Scalability in port counts– Flexibility in spectral allocation– Fast switching times– Green low-power operation