Re: [10GMMF] Task 2 and 4 slides for meeting Dec15th - OM3 fibr e measurements
Jonathan,
I have one comment about your PIE-D calculation. In order to have
consistent results we must use exactly the same simulating conditions.
According to Sudeep suggestion, PIE-D due to fiber impairments should be
calculated assuming the following set-up:
1 - Impulsive (Delta-like) PPG with PRBS pattern
2 - Gaussian laser impulse response with 47.1ps rise time
3 - Fourth order Bessel-Thompson filter in the receiver section.
This is the background test bed for PIE-D calculation. The impulse
response of the fiber link determines the PIE-D evaluated at the
receiver output. I have one warning about this test-bed. The background
PIE-D, meaning back-to-back assuming above set-up gives about 2.8dBo
PIE-D. Should this value accounted for complete channel PIE-D
characterization? I guess it should be. In this case we will never
acieve PIE-D less then the above background value. Of course, changing
laser rise time many different background PIE-D values would be
achievable, but it is essential we all agree on this test-bed otherwise
conclusions would not be comparable.
Best regards
Stefano
-----Original Message-----
From: owner-stds-802-3-10gmmf@IEEE.ORG
[mailto:owner-stds-802-3-10gmmf@IEEE.ORG] On Behalf Of Jonathan King
Sent: Mittwoch, 15. Dezember 2004 18:28
To: STDS-802-3-10GMMF@listserv.ieee.org
Subject: Re: [10GMMF] Task 2 and 4 slides for meeting Dec15th - OM3 fibr
e measurements
Hi John
I think misled you with my colour coding - my intention was to make a
flat table a little bit easier to interpret visually. I'm very
definitely not trying to infer a unanimous fail at 5.5dB PIE-D, or
unanimous pass at 4.0dB!
thanks for the rest of your comments
look forward to speaking with you on the call this morning
best wishes
Jonathan
tel: 1 408 524 5110
e-mail: jking@bigbearnetworks.com
fax: 1 408 739 0568
Jonathan King
Director, Optical Systems
BigBear Networks
345 Potrero Avenue
Sunnyvale, CA 94085
-----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: Wednesday, December 15, 2004 7:59 AM
To: STDS-802-3-10GMMF@listserv.ieee.org
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
has
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 500MHz.km 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
To: STDS-802-3-10GMMF@listserv.ieee.org
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
Jonathan
tel: 1 408 524 5110
e-mail: jking@bigbearnetworks.com
fax: 1 408 739 0568
Jonathan King
Director, Optical Systems
BigBear Networks
345 Potrero Avenue
Sunnyvale, CA 94085