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RE: spreadsheet for MMF, reprise


Perhaps we are mixing apples and oranges here. Because of FDDI, 500 MHz•km
62.5 um fiber is very common in my part of the country. That same fiber is
also rated 160 MHz•km. The key is the operating wavelength. For the example
given, 500 MHz•km correlates to 1300 nm, 160 to 850 nm. Both are true for
the same optical fiber. If I missed your point, I apologize.

Michael Griffin

Subject:  RE: spreadsheet for MMF

You Wrote:
  I have noticed a bit of confusion when it comes to discussing "installed
base".  Your pdf document has prompted me to make the following points.
1) You discuss "500 MHz*km" installed fiber.  According to the surveys
presented to this group, that is not a significant fraction of the
2) The 100-m installed base objective of the HSSG is to support any fiber
the installed base (look at the minutes for an explanation, I'm working
memory).  Your 500 MHz*km fiber may meet that objective (in my opinion) but
not in such a dramatic way that it would prompt support for another PMD.
you really want a PMD that works for >90% of the installed base I think
we're talking 200 MHz*km (160 MHz*km worst case).
3) The chart developed in Dallas was based on 160 MHz*km, not on the HSSG
installed base objective.  The point was raised by Bob Grow, but dismissed
by Jonathan because we were just making comparisons not checking which PMDs
met the HSSG objectives.

Robert Marsland
Focused Research, Inc. (a New Focus company)
555 Science Dr.
Madison, WI 53711
(608) 238 2455
(608) 238 2656 FAX