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Re: [10GMMF] Task 2 and 4 slides for meeting Dec15th - OM3 fibr e measurements

Please I have to slight correct the PIE-D values I gave in my previous
mail. I just recalculated it and assuming the background set-up
(Impulsive PPG) I found PIE-D=1.55dBo (PIE-L=2.03dBo). Assuming smoothed
trapezoid PPG (20ps rise time convolved with a Gaussian, 10ps sigma)
gave PIE-D=2.28dBo (PIE-L=3.35dBo).



-----Original Message-----
From: owner-stds-802-3-10gmmf@IEEE.ORG
[mailto:owner-stds-802-3-10gmmf@IEEE.ORG] On Behalf Of Abbott, John S Dr
Sent: Mittwoch, 15. Dezember 2004 16:59
Subject: Re: [10GMMF] Task 2 and 4 slides for meeting Dec15th - OM3 fibr
e measurements

Jonathan, thanks for the comprehensive measurements.

1. Jonathan's use of green-yellow-red is exactly the breakdown that I
was trying to achieve in my motion at San Antonio where we would
tentatively designate one value of PIE-D as a pass (i.e. GREEN) and
another value of PIE-D as a fail (i.e. RED) with a gap in between
(YELLOW).  I think he gets the point across much better than I did.
        Here Jonathan is proposing unanimous pass = 4.0dB (GREEN)
                                         unanimous fail = 5.5dB (RED)
   At the San Antonio meeting discussion on this 3-level sorting
        we received input that a PIE-D over 5.0 was unacceptable.
        Jonathan puts that in the yellow category.

2. In doing experiments on the various demo cables the 802.3aq task
        force needs to remember that for the most part these are
        not worst case fibers, but rather typical fibers.  In the case
         of the OM3 demo cables Jonathan tested, one cable was supposed
         to be "interesting" with DMD artifacts to test our
        specification-setting, and one cable was supposed to be
        "good" with all fibers expected to work at 10GbE 300m 850nm.
        It is not obvious to me from Jonathan's data but the B- cable
        the better fibers.
3. This data seems to suggest to me that not only is a there a
consistent problem if an offset patchcord is used but that the use of
connectors with center launches will also occasionally have problems.
The 4.9dB PIE-D value on the champion White fiber really suggests that
values over 5.0dB will not be rare. 4.  One idea I'd like to mention for
discussion: For handling the data from demo cables to generate PIE-D, in
some cases we might be able to make more rigorous estimates by scaling
the impulse response (the DMD data) so that it just meets the spec. For
example on the 12/96 FDDI cable, scale the impulse response consistent
with a 160/500 FDDI spec for OM1 or 500/500 {or 400/400} for OM2. This
also allows us to use fibers whose OFL BW fell slightly below
by tightening the impulse response to increase it to 500.  It also
provides a route to use some of the historical data HP measured on the
installed base.  In the case of the OM3 fibers, we have round robin DMD
and OFL data and can scale the impulse response so that they just meet
the DMD mask.  I don't think this fully addresses the issue of "worst
case fibers" but it might be a step in that direction. 5. Finally I
wonder in examples like this if some of the measurements should be
repeated so we know how much is "noise" and how much is repeatable.

John A.

-----Original Message-----
From: Jonathan King [mailto:jking@BIGBEARNETWORKS.COM]
Sent: Tuesday, December 14, 2004 5:22 PM
Subject: Re: [10GMMF] Task 2 and 4 slides for meeting Dec15th - OM3
fibre measurements

Here are some measurements of OM3 fibre PIE-D values for various launch
conditions, contribution for task 2 and 4 meeting on wednesday 15th Dec
04 best wishes


tel: 1 408 524 5110
fax: 1 408 739 0568

Jonathan King
Director, Optical Systems
BigBear Networks
345 Potrero Avenue
Sunnyvale, CA 94085