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


Jonathan,
I'm not sure I follow you with regard to your concern on 10GMMF.  If you refer to OM3 fiber, the modal noise concerns are similar to that of mixing legacy 50 um and 62 um fibers because its core size is the same as other 50 um fibers.  Perhaps you are thinking of other impairments.

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 Thatcher <jonathan.thatcher@ieee.org>
Sent by: owner-stds-802-3-10gmmf@listserv.ieee.org

08/20/2004 11:47 AM
Please respond to jonathan.thatcher

       
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        cc:        (bcc: Paul F Kolesar/CommScope)
        Subject:        Re: [10GMMF] 62MMF connector loss and draft test link config



Paul,
 
I don't think any of us would recommend this as a good practice. The question is, should we condemn it as bad practice? As you are probably aware, the vast majority of 1G and 10G links work just fine with mixed 50/62.6 cable plant (as few operate at the extreme corners of the specification). I'm dubious about 10GMMF "working just fine."
-----Original Message-----
From: owner-stds-802-3-10gmmf@LISTSERV.IEEE.ORG [mailto:owner-stds-802-3-10gmmf@LISTSERV.IEEE.ORG]On Behalf Of Paul Kolesar
Sent: Friday, August 20, 2004 8:39 AM
To: STDS-802-3-10GMMF@LISTSERV.IEEE.ORG
Subject: Re: [10GMMF] 62MMF connector loss and draft test link config

Jonathan,
Systimax Solutions has never recommended mixing core sizes within a channel. While it may be tolerated by LED-based applications by accounting for the extra insertion loss, laser-based applications have the potential to generate more modal noise.  Given that the loss between 62 and 50 um can range upwards to over 4 dB, depending on the mode fill of the 62 um fiber, the modal noise effects could be significant.  This is an area in need of study if mixing of core sizes is deemed desirable.  But up to now, Systimax Solutions has simply not supported it.

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 Thatcher <jonathan.thatcher@IEEE.ORG>
Sent by: owner-stds-802-3-10gmmf@listserv.ieee.org

08/20/2004 09:51 AM
Please respond to jonathan.thatcher

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





This thread  brings up an interesting question. In the past, we have never
written into the standard any requirements, or even guidance regarding a mix
of 50 and 62.5 micron fiber. Need we now?

jonathan