Re: [10GMMF] 62MMF connector loss and draft test link config

[Paul Kolesar <PKOLESAR@xxxxxxxxxxxx>]

David,
thanks for this work.  The model
I have for 62.5 agrees with your analysis for the steady state launch condition.
 Please confirm that in your model the steady state condition represents
a 70/70 launch (i.e. 70% of maximum core diameter and 70% of maximum NA).
 

I have a comment regarding the 7 um
limit. The 7 um value was chosen for the OM3 work because it represented
0.5 dB for 50 um fiber under steady state conditions.  The remaining
0.25 dB needed to reach the 0.75 dB limit was allotted to mechanisms other
than lateral offset.  The equivalent offset for 62 um fiber is 9 um
from your graph.  Thus connectors need to be of tighter tolerance
for 50 um fiber than for 62 um fiber.  As product lines of cabling
vendors in North America and other parts of the world have shifted to include
a larger mix of 50 um fiber, the tolerance for connectors needed to be
tightened to maintain good performance.  Fortunately progress in connector
technology permitted this.  The result is that over time connectors
have gotten better.  This leads to an interesting issue when dealing
with legacy plant. The older plant likely has poorer connectors due to
both tolerance and wear.  I think this leads to a need for considering
different values for legacy 50 and 62 um plants.  To address these
considerations, I would suggest that the limit for 62 um fiber be set at
9 um and that for 50 set at 7 um.


Regards,
Paul Kolesar
SYSTIMAX® SOLUTIONS
1300 East Lookout Drive 
Richardson, TX 75082 
Phone:  972.792.3155
Fax:      972.792.3111
eMail:   pkolesar@systimax.com

David Cunningham <david_cunningham@AGILENT.COM> Sent by: owner-stds-802-3-10gmmf@listserv.ieee.org 08/18/2004 02:24 PM Please respond to "IEEE 802.3aq 10GBASE-LRM"

To:        STDS-802-3-10GMMF@listserv.ieee.org         cc:        (bcc: Paul F Kolesar/CommScope)         Subject:        [10GMMF] 62MMF connector loss and draft test link config

Dear All,

As promised on todays Fiber Channel Ad Hoc I attach a PDF file containing
the following information:

* My calculated graphs of connector loss versus offset for overfilled launch,
steady state launch and 23 um offset single mode launch.

* The agreed draft of the worst-case test configuration for channel time
variation measurements with comments from our call to document our reasoning
behind the chosen configuration.

Regards,
David