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RE: PMD discussion


A question for you.

If you read Walter's statement carefully, then sent out your comment.  I
believe your are proposing 4 PMDs.  Correct?


Edward S. Chang
NetWorth Technologies, Inc.
Tel: (610)292-2870
Fax: (610)292-2872

-----Original Message-----
[]On Behalf Of Seto, Koichiro
Sent: Monday, May 29, 2000 10:25 AM
Subject: Re: PMD discussion

[Date: 05/29/2000  From Seto]


My understanding is that the following set is also one of the top favorites:

________________optimized for	may be used for
1310 nm WWDM	MMF upto 300m	SMF upto 10km
1310 nm Serial	SMF upto 10km	MMF upto 86m
1550 nm Serial	SMF upto 40km

I understand there are some risks that 850nm-WWDM solution may not satisfy
laser eye safety as Jonathan pointed out in the discussion on Thursday.
Also, I learned that there are some risks that 1310nm-WWDM may not be able
to achieve 10km at SMF if not impossible.  At least we have not seen any
data that would prove the feasibility of 1310nm-WWDM over 10km SMF.  It is
not to say that this can not be done, but I have not been convinced that the
 same 1310nm-WWDM optics at same cost factor will serve for both 300m MMF
and 10km SMF.  Also, some people pointed out that 1310nm-Serial can be built
 at cost factors of x1.8 to 850nm-Serial while 1310nm-WWDM is x3.  If we can
 achieve the same goal (SMF 10km), the cheaper is the better.

I hope no one is offended by my not-so-educated opinion.  I would appreciate
 a healthy discussion.


> First of all, thanks to everybody that presented PMD proposals at the last
> meeting. I've sent my presentation to David Law, so it should be available
> on the web site in the next couple of days.
> In listening to the discussion after my presentation and then going around
> and talking to people, it feels to me like we're starting to converge. Not
> there, yet, but making progress.
> The equipment manufacturers made it pretty clear they would like to see no
> more than 3 PMDs in the standard. The PMD vendors have some concern that
> using only 3 PMDs may sub-optimize certain objectives, however, they could
> support the 3 PMD position if it is made clear which 3 PMDs the equipment
> oems want.
> Based on an informal straw poll and anecdotal evidence, my opinion is the
> first choice would be the set:
> ________________
> 850 nm WWDM
> 1310 nm WWDM
> 1550 nm Serial
> ________________
> If that set isn't feasible, then the 2nd most popular choice is:
> ________________
> 850 nm WWDM
> 1310 nm Serial
> 1550 nm Serial
> ________________
> Thoughts, feedback?
> Walt
> ___________________
> Walter Thirion
> Chair, IEEE 802.3ae PMD Sub-Task Force
> 301 Congress Ave.
> Suite 2050
> Austin, Texas 78701
> Voice:	512-236-6951
> Fax:	512-236-6959
> ___________________