Jonathan,
I agree that the table contents are
what we agreed on the call yesterday. In looking more closely, I
note that one of the values for OM1 launch appear to allow launches way
outside those produced by compliant 62.5 um offset launch patch cords.
I will suggest an adjustment based on Joerg's Encircled Flux plots.
The Encircled Flux definition for OM1
is correct on the 24 um radial limit for 86% EF. However, it does
not properly reflect the allowed power near the core center. We touched
briefly on this at the end of the call, but did not have the chance to
think it thru at that point. Now, with the time to look more closely,
I see a clear need for adjustment. If left as is, the proposal allows
singlemode launches offset by as little as 5 um! According to Joerg's
EF calculations, for OSL cords with 20 +/- 3 um offsets, no compliant cord
would produce 30% EF until the encircled radius expanded beyond 10 um.
At the presently suggested 4.5 um radius, the maximum allowable EFshould
be about 8%. A number of better radius-percentage combinations are
possible. Avoiding the crowded region on Joerg's plots when EF is
less than 10% leads to consideration of values between 10 and 30%.
It appears that either <20% in 7.5 um or <30% within 10 um
radius are good combinations. The latter percentage has the
advantage of being consistent with the proposed OM2 and OM3 specs on the
inner region power, so is my recommendation. Please replace the present
values with "<30% in 10 um radius".
I invite discussion to drive consensus.
Regards,
Paul Kolesar
SYSTIMAX® SOLUTIONS
1300 East Lookout Drive
Richardson, TX 75082
Phone: 972.792.3155
Fax: 972.792.3111
eMail: pkolesar@systimax.com
Jonathan King <jking@BIGBEARNETWORKS.COM> Sent by: owner-stds-802-3-10gmmf@ieee.org
12/15/2004 09:32 PM
Please respond to
"IEEE P802.3aq 10GBASE-LRM" <stds-802-3-10gmmf@ieee.org>
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Subject
Re: [10GMMF] Task 2 and 4- launch
recommendations rev0.1 following Dec15th meeting
Dear Task 2 and 4 participants
Thanks to all for a very rich and useful discussion today
here is a revised slide of the 'primary' launch recommendations with
amendments agreed during the Dec 15th call
Please let me know if I've missed anything, or if you have comments or
suggestions