18 aug 2004ieee802.3aq channel model ad hoc task 2: time-varying study & modal noise 1...

18 Aug 2004 IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

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

Teleconference notes, 18 August 2004Jonathan King


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Agenda

1) attendees

2) agree last meeting notes

3) Presentationsa) Summary connector loss and standard link proposal- David

Cunningham

b) Measurement of time variance in MMF - Robert Coenen, Scintera

4) other business -

5) 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, Phyworksplease 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) Presentationsa) 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 noiseVibration 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.

Launch loss due to lateral offset Offset loss due to lateral offset offset

OFL 0.75dB 6um 0.5dB 4um

OSL 0.75dB 8um 0.5dB 7um

steady state 0.75dB 11um 0.5dB 9um


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3) Presentations cont'd

b) Measurement of time variance in MMF - Robert CoenenA 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.

5) Next meeting

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

4) Other business

No issues raised

18 aug 2004ieee802.3aq channel model ad hoc task 2: time-varying study & modal noise 1...

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