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RE: Your 3PMD Proposal


The 850 nm CWDM was presented in Ottawa meeting with all the link and PMD
details.  If you are interested in the details, you can find them in my


Also, Bill Wiedemann of BLAZE presented a 850 nm CWDM related paper in
Ottawa may meeting. You can ask him his presentation.


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

Del and Piers, your presentation
a proposed set of three PMD's includes 1310 WWDM, but not 850 WWDM.
to slide #6  "Comparison of PMD Technologies" in the presentation by Jim
(,  it
looks like the only advantage of 1300  WWDM over 850 WWDM is that it can
lengths up to 300m, compared to 100m for 850 WWDM.  Also, 1300 WWDM can
up to 10Km on SMF, but your proposed 1300 serial PMD looks like a better
solution at 10Km because of its lower cost.

According to the referenced slide, 850 WWDM is half the cost of 1300 WWDM
can reach lengths up to 550m on the new 50um fiber with a bandwidth of
2000MHz*km for 850nm.  Based on this information, it looks like the only
advantage of using 1300 WWDM over 850 WWDM is that it can reach 300m on
installed 62.5um fiber.

Is this analysis correct and, if so, do you feel that the extra length
by 1300 WWDM on installed MMF is worth the extra cost?



Lawrence J. Rennie
National Semiconductor Corporation
Calabasas, CA.
818 880 2720