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Re: MMF PMD Selection

Title: MMF PMD Selection
I supported the 3-PMD because I firmly believe that less the number of PMDs we have to support,
higher the volume for each PMD, and the lower the cost will be.
The working group has voted for 1550 nm and 1310 nm serial to support Application 1 and 2.  If the
equalization scheme turns out to work well, the short wavelength 850 nm 4-CWDM should be the
lowest cost solution that will address Application 3.  We will still end up with 3-PMD. What about
eye safety? Either OFC or the new eye safety standard will address it.
Wenbin Jiang
----- Original Message -----
Sent: Wednesday, July 19, 2000 10:41 AM
Subject: MMF PMD Selection


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

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.


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


    -----Original Message-----
    From:   Bill Wiedemann [SMTP:billw@xxxxxxxxxxx]
    Sent:   Monday, July 17, 2000 9:34 PM
    To:     stds-802-3-hssg
    Subject:        RE: what's next ?

    Jonathan, Thanks for your clarification on expectations for the interim
    meeting in September.

    I think it would be very helpful to have a discussion as to the "systems"
    vendors desires.

    For example their interest in the current candidates for the 100 meter and
    300 meter objectives. 1300WWDM, 850CWDM, 850 serial.

    What they would "need" to see/understand for these to gain their support,
    and/or why they never will support one or all of these.  My reason for
    initiating this is that it will be very difficult to get any of these
    approved unless we meet their expectations. I hope any of these aren't
    approved as the lesser of evils.

    Regarding 850CWDM we are planning to make first implementations with duplex
    SC moving to LC with small form factors.  Our expectation is that small form
    factor with LC could be available a year from today.  First size will be
    GBIC, electrical interface can be XGMII or XAUI for first implementations.
    Should we pursue equalization for 850CWDM to reach 300 meters over legacy
    62.5 um fiber?

    We have had initial discussions with Brad Booth and David Cunningham to be
    sure that the clauses for WDM implementations keep up with the current
    progress on serial clauses.

    Bill Wiedemann
    925-560-1610  X169