IEEE802.3aq Channel model ad hoc Task 2: Time-varying study & modal noise (revised)

1. IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise(revised) Teleconference notes, 1 Dec 2004 Jonathan King IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

2. Agenda • attendees • Task 2 • status after the Nov04 meeting • discussion of residual items on task 2 • Joint task 2 and task 4 • launch study discussion • other business • next meeting date/time IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

3. 1) Attendees • Jonathan King, Big Bear Networks • Yu Sun, Optium • John Jaeger, Big Bear Networks • Sudeep Bhoja, Big Bear Networks • David Cunningham, Agilent • Petre Popescu, Quake • John Ewen, JDSU • Paul Kolesar, Systimax • John Abbott, Corning • Al Brunsting, Panduit • Andre van Schyndel, Bookham • Jonathan Ingham, Cambridge • Pete Hallemeier, Optium IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

4. 2) Task 2 a) Review of task 2 status following November meeting Input has been provided to the channel ad hoc on all task 2 study areas, including channel time variation effects and rates, and modal noise. At the San Antonio meeting, Nov '04, it was agreed that the slow rate of channel variation did not require a normative dynamic test, but an informative note could be added to the draft, and that 0.5dB modal noise penalty budget was sufficient . b) Residual work items for task 2 Comments following: Petre Popescu agreed to complete the 2 remaining temperature study items. Discussion of the modal noise work determined that it covers FP & DFB lasers, since a 3 mode laser model is assumed, as used in 1GigE). Discussion of the content of the informative note on channel time variation: it was suggested that the note should include a description of the relationship between variation rate and magnitude of channel change, and it was agreed that the editor should be asked to include an editors note (based on the recommendation included in Cunningham_1_1104) which informatively alerts implementers that the channel impulse response may vary at 10’s of Hz and recommend that the equalizer adaptation time be faster than this. Paul Kolesar also agreed to write down his thoughts on an informative dynamic channel test. IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

5. 3) Task 2 & 4: joint activity on launch study - 1 a) Suggested goals and tasks for the study of launch were presented and discussed Notes of goals and tasks agreed to : Main goal : To provide a specific input to the task force on launch conditions and launch testing, for the January '05 meeting Tasks and study areas : Simulations of coverage vs PIE-D plots as output (for various launch conditions Agree common model for simulations (e.g. connector offsets, rise times, per offset statistics) Recommend (simple) launch compliance test Measurements of real fibres Develop a channel model for OM2 Notes on discussion following Yu Sun described work so far in task 4 which has agreed a 4 connector link model with offsets at a) worst case and b) average values. Joerg Kropp offered to present some calculations and experimental results on OM3 fibres for the next meeting David Cunningham offered measurements and theory of different launches on TIA and other fibre sets, for the first or second week of January. Launch types would be described by encircled flux definitions, and include centre, offset and vortex type launches IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

6. 3) Task 2 & 4: joint activity on launch study - 2 Yu Sun offered to compare IPR statistics for cambridge and monte carlo sets with and without polarization rotation - if the statistics are close enough, then modeling the polarisation effect explicitly can be avoided, since it isn't adding new channel responses. John Jaeger also offered measurements and simulations of different launches on some of the TIA round robin fibres. John Ewen offered to present some simulation work on launches for OM3 fibres on 15th Dec'04. David Cunningham commented that a choice of two launches such as centre launch and an offset launch, could improve coverage. He also noted that customers want to use one of the existing mode conditioning patchcords, and that the concept of a universal launch would still be desirable to customers if practical. In the discussion on optimum launch for OM2 fibre, John Abbott agreed to draft of issues and considerations likely to impact a model of OM2 fibres - there are OM1 like central defect issues, but smaller OM3 like 'alpha p' issues. It was agreed that generating an OM2 model should be a task 1 development and that Prof. Ian Whites team would be involved. It was noted that given OM2's dual window of optimization, the launch constraints may be weaker than for OM1 or OM2, which may simplify the OM2 model requirement. Several on the call expressed support for an implementation non-specific launch compliance test, such as encircled flux; it was noted that both centre launch and offset type launches could be described this way. IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise

7. 4) Other business - no issues raised 5) Next meeting • Wednesday 8th December 2004 9.30am PCT IEEE802.3aq Channel model ad hocTask 2: Time-varying study & modal noise