IEEE802'3aq Channel model ad hoc Task 2: Timevarying study

1
IEEE802.3aq Channel model ad hocTask 2
Time-varying study modal noise

• Teleconference notes, 18 August 2004
• Jonathan King

2
Agenda

• attendees
• agree last meeting notes
• Presentations
• Summary connector loss and standard link
  proposal- David Cunningham
• Measurement of time variance in MMF - Robert
  Coenen, Scintera
• other business -
• next meeting date/time

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1) Attendees

• Jonathan King, Big Bear Networks
• Piers Dawe, Agilent
• David Cunningham, Agilent
• Petre Popescu, Quake
• Tremont Maio, Analog
• Ali Ghiasi,
• John Dallesasse, Emcore
• Yu Sun, Optium
• Jens Fiedler, Infineon
• Jesper Hanberg, Intel
• Ryan Latchman, Genum
• Norm Swanson, Clariphy
• Tom Lindsey, Clariphy
• Lars Thon, Aeluros
• Robert Coenen, Scintera
• Gary Schaulov,
• Al Brunsting, Panduit
• Chet Babla, Phyworks
• please let me know if you or your organization
  have been missed

2) Minutes of last meeting agreed - no issues
raised
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3) Presentations

• a) Update on connector loss calculations and
  standard link proposal - David Cunningham
• David summarized his work on connector loss vs
  offsets for OFL, OSL launches and steady state
  mode power distribution.
• Discussion of Maximum offset discussion It
  was noted that legacy links were spec'd for worst
  case individual connector loss of 0.75 dB with
  LEDs (OFL launch) at maximum 0.75dB loss per
  connector (ISO 11801 standard) suggesting a
  maximum 6-7micron offset. OM3 group settled on a
  7micron offset based on 0.5dB loss due to lateral
  offset for steady state mode power distribution
  and 0.25dB other loss. Gigabit Ethernet used a 2
  connector link model with 0.75dB loss per
  connector. There was general support on
  the call for 7microns as a reasonable worst case
  connector offset based on the evidence presented.
  There was also general support for a draft
  standard link with 4 connections 1 single mode
  connection, 2 multimode connections at a
  maximum 7micron offset, 1 multimode connection at
  below 4 microns to keep the standard link within
  connector loss budget.
• Worst case offset position in the link It was
  agreed that having the highest offset connections
  nearest to the transmitter would represent the
  worst case for modal noise
• Vibration of connector offset After some
  discussion it was agreed that connector offset
  would not be affected by vibration because spring
  loaded insertion and receptacle sleeve inserts
  would prevent movement. It was agreed that fibre
  movement was expected to be the significant
  factor in time variance of the link.
• After the discussion, David Cunningham
  volunteered to assemble and distribute a draft
  summary of the agreed link configuration and
  supporting evidence for the values agreed upon,
  for discussion by the wider LRM group.

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3) Presentations cont'd

• b) Measurement of time variance in MMF - Robert
  Coenen
• A review of Roberts updated document on
  measuring the effect of vibration on a MMF link.
• Discussion following Worst case position
  in a link for fibre movement/vibration was
  discussed concensus was that the worst place for
  modal noise was at the start of the multimode
  link, after any OSL patchcord and between the
  highest mode selective losses (this is
  consistent with Gigabit Ethernet approach). It
  was also agreed that a polarization controller
  should be included in a standard link model and
  set to maximize time variation effects.

4) Other business
No issues raised
5) Next meeting

• Wednesday 25th August 9am PCT, 5pm UK