Progress in Optical Networking

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Progress in Optical Networking

• Paul Green
• IEEE Communication Magazine
• January 2001
• KyoungHee Lee CS Dept.
• 26 September 2002

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Contents

• Abstract
• Perspective
• Why All-Optical network?
• What is the current status?
• How did we get here?
• What remains to be done?

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Abstract

• Summarizes,
• The present state of optical networking
• How we got to this point
• What needs to be done to complete the job

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Perspective

• Optical Networks
• Opaque the path between end users is interrupted
  at intermediate nodes by OEO conversion operation
• SONET/SDH
• WDM
• All-Optical each connection is totally optical
  except at the end nodes
• Single-wavelength
• DWDM(Dense wavelength division multiplexing)
• Has more than 8 wavelengths

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?OC(Optical Carrier Level)
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Why All-Optical Networks?

• The stupendous bandwidth available
• 1.5?
• 25,000 GHz
• Completely lacks protocol dependency
• Old protocols may be given artificial respiration
  to extend their lifespan
• New ones may be brought online quickly
• Functional simplicity
• Lowers first cost
• Offers service lifetime savings
• Intrinsic robustness

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What is the Current Status?-Network layers

• Being converged to a two-layer communication
  infrastructure

• ATM function is being absorbed into IP
• Transport capability of SONET/SDH is being
  absorbed by the optical layer

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What is the Current Status?(Cont.)-The Optical
and IP layers the topology view/layer view
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How did we get here? -At the historical
level

• The first step towards all-optical networks
• Bellcore and British Telecom, 15 years ago
• The first laboratory prototype
• Lambdanet of Bellcore, 1990
• The first deployed network
• Rainbow-1 of IBM, 1991
• The first commercial DWDM product
• - Next Generation Lightwave Network of ATT and
  Muxmaster of IBM, 1995
• WDM fiber pipes being extensively installed, 1996
• A few primitive OADMs with frozen paths, 1998
• OADMs are commercially available, today
• Large-N OXCs, in the future

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How did we get here? -At the technical level

• Progress are mainly due to advances in
  these six areas
• Improved architecture understanding
• Developments in purely optical crossconnects
• More channels of higher bit rate
• New kinds of fiber and amplifiers
• Longer lightpaths
• Lower technology costs

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What remains to be done?

• To increase the number of WDM channels, their
  length, and their bit rates
• All-optical way of doing wavelength conversion
• Need for a widely adopted standard
• Challenge of component cost reduction