On Fri, 19 May 2006 14:24:07 -0500, Tom Ring
wrote:
And a web search produced a couple very good links out of the first 20.
One was a great discussion of problems in long optical fibers, and
some relatively simple ways to work around some of them, or at least to
mitigate them.

Hi Tom,

In my early days in this game (late 80s), I sought to turn lemons into
quantum-aide. That is, I sought erbium doped fiber optics to amplify
nanowatt fluorescence signals with 10 to 50 µS decay times. Not one
of those off-the-shelf commodities, however; so I had to amplify in
the conventional way with an PMT.

For those interested, long haul communications fiber optics
(transoceanic grade) met with the same requirements for amplifiers
placed along the length to maintain S+N/N. Erbium doped fibers were
projected as a solution. You could pulse UV into the fiber to charge
it, and a IR data pulse would be amplified, continuously along its
length. The IR data pulse would be boosted by the previous charge of
energy. This is an example of forward Raman scattering and is called
Raman Amplification (which at the time would have been about 30dB and
10% efficient).

73's
Richard Clark, KB7QHC