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RE: MMF PMD Selection

Title: MMF PMD Selection
David,
It seems that your primary motive for selecting 1300WWDM is that it can meet 300 meters over legacy 62.5 micron fiber.
What would your position be if 850CWDM could meet 300 meters over the installed base.  Without getting into any absolute numbers or relative ratios, I am sure you know that producing a short wavelength solution (850CWDM) is less expensive than a long wavelength solution (1300WWDM).  How much less expensive does 850CWDM have to be for you to prefer it over 1300WWDM.
 
FYI your reference to cost coming down on 1300WWDM to similar to 850CWDM when 1300 VCSELs are available should be discussed as my information is that the cost difference between 1300WWDM and 850CWDM is not due to the cost of the lasers.  It is primarily due to single mode alignments required on the 1300WWDM while only multimode placements are needed for 850CWDM.
 
850CWDM is the optimal solution for the largest market segment.   If 850CWDM needs to be made more desirable by addressing legacy 62.5 micron fiber to 300 meters, let the customers speak.  Understand that the existing 850CWDM proposal meets the existing objectives, 100 meters over installed (legacy 62.5 micron) mmf, and 300 meters over MMF (500 MHz.km standard 50 micron).
 
Cheers
 
Bill Wiedemann
925-560-1610  x169
-----Original Message-----
From: owner-stds-802-3-hssg@xxxxxxxx [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of David Martin
Sent: Wednesday, July 19, 2000 10:41 AM
To: stds-802-3-hssg
Subject: MMF PMD Selection


All,

In the interest of making progress on the MMF PMD selection, and in
response to Bill's request for system vendor input, I'll paint a bright
red target on myself. Here goes.

Consider the following four distinct applications:

  1. Dark fiber/SMF runs up to 40km & WAN interconnect (metro)
  2. Dark fiber/SMF runs up to 10km & WAN interconnect (campus backbone)
  3. MMF horizontal/vertical runs up to 100/300m (in-building)
  4. New fiber (any type: ribbon, MMF, SMF) runs up to 300m (intra-office)

It is easiest to explain to customers what to deploy when there is a PMD
positioned to match each application (or ideally one that does all).  I voted
serial 1550 for app-1, serial 1310 for app-2, 1300 WWDM for app-3 and
left app-4 for the OIF VSR work activity (as we don't have a general intra-
office interconnect objective, but could adopt/adapt their results in a later
effort).

So why pick 1300 WWDM for app-3? My thinking:

  1. It is the only solution which addresses up to 300m for all installed base.

    That is really the end of the rationale. However, considering cost arguments:

  2. 1300 VCSELs are supposedly only 6 months away (or up to 6 years

away depending on the source), which should make 1300 WWDM cost
competitive with 850 VCSEL WWDM.

Now I'll duck & cover.

...Dave

David W. Martin
Nortel Networks
+1 613 765-2901  
+1 613 763-2388 (fax)
dwmartin@xxxxxxxxxxxxxxxxxx

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