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Hi Brian, I would like to make you aware of an issue that was discovered in the current specifications during the offline discussions, by either Mike or David (don’t remember which one of the two). For 100GBASE-FR1, 100GBASE-LR1, 400GBASE-FR4 and 400GBASE-LR4-6 it turned out that in the flat part of the OMA/RS curves, there is 0.1 dB shortage in power budget for ER < 4.5 dB, because the
knee in the OMA versus TDECQ curve is at 1.3 dB instead of 1.4 dB for ER > 4.5 dB.
Thus the budget is OK in the linear increase part, but not in the flat part for ER < 4.5 dB. We generally thought that this required fixing and we explored several ways of doing this with the current proposal the most straightforward and simple way. You may find that for 100GBASE-DR this power budget decrease is 0.3 dB instead of 0.1 dB for the cu cases. So for DR in the linear increase part, the budget is 3.4 dB for ER > 5 dB, whereas in the flat part, it is only 3.1 dB, which is 0.3 dB short. The reason for DR is that the knee for OMA min is at TDECQ = 1.1 dB instead of TECQ = 1.4 dB for RS. Please check. Kind regards, Peter From: Brian Welch (bpwelch) [mailto:00000e3f3facf699-dmarc-request@xxxxxxxxxxxxxxxxx]
Mark/All, I won’t have a presentation for Tuesday, but I did want to follow up on a discussion that was had in our prior meeting. In the presentation “Nicholl_3cu_051920” there was documented an attempt to reconcile
several comments, including to simplify specifications are it regards different extinction ratio ranges (“high” vs “low” ER). One thing that first became apparent to me during this meeting was that the proposal to do this resulted in an increase in the power
budgets for the 100G/L specs of 0.1dB (for high ER), and subsequently an increase in OMA specifications by the same amount. While I’m not opposed to simplifying the spec, I would prefer to do it in a way that doesn’t end up also making it more stringent. While 0.1dB may seem like a trivial amount the effect of the change can be
real, especially in how moving a spec limit will degrade the manufacturing statistics of a part (reduced Cpk, which could drive more stringent testing requirements, amount other things). The optics world today is one where gains are often found a fraction
of a dB at a time, so to sacrifice some of those gains when it is not absolutely necessary seems unfortunate to me. As such my preference for now would be to keep the transmitter specs (and power budgets) as they are, where we report “OMA-TDECQ” for two extinction ratio ranges (consistent with how it is specified for 100GBASE-DR
and 400GBASE-DR4). I would be interested in others thoughts on this matter.
Thanks, Brian From: Mark Nowell (mnowell) <00000b59be7040a9-dmarc-request@xxxxxxxxxxxxxxxxx>
Dear Colleagues, This is a reminder about our deadline for presentation requests for next week’s P802.3cu Interim teleconference. Please send me your presentation requests by Thursday May 21st (today) and send me the presentation by Friday May 22nd (tomorrow). A reminder that with the limited time
we have for these teleconferences, presentation time will be limited to no more than 15 mins. Please note that All interim teleconference meeting participants should review the following documents prior to participation in an interim meeting teleconference:
All of these policies may be found at http://ieee802.org/3/policies.html. Regards, Mark To unsubscribe from the STDS-802-3-100G-OPTX list, click the following link:
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