With regards to suggested EDFA amplification tricks and similar: If
the requirement is not > 150km@1G or 80km@10G/DWDM then I personally
strongly disencourage the use of optical amps. 200km / 41dB 1G SFPs
are available with costs way below dual EDFAs plus spare, and the
chance for the untrained to get eye damages in the process of
implementation is far less. So put some laser googles at around 400
USD/each to the purchase list. If one decides to do so then add a
post-amplifier on each *end* of the fiber link to increase the signal
before hitting the receiver, and do not pump in star-wars class laser
power at the beginning 
.
Depends where you buy your EDFAs, I suspect you could probably get them
for less than the cost of a single channel of super long reach optics if
you tried hard enough.
Respectfully disagree here - been there (googled^H^Hmarket research, talked to both manufactures and resellers for the last year), bought sample and went through lab tests. Still was unable to find trustful/working EDFAs near the cost of a pair of 40dB SFPs. 200km SFPs are even cheaper than 'original' Cisco CWDM-SFPs (standard 80km). We have them on stock for resale (no commercials intended here), so this price indication is near real-time
If you needed to add DWDM later on, and/or
dispersion compensation for 10G links the EDFAs will be needed anyways,
so sometimes it just makes sense to solve the problem once with an amp
rather than trying to solve it on a per-channel basis.
It depends on the requirement - of course.
When Mike is heading for 10G DWDM demand levels he will probably have to amplify and cromatic-disperse-compensate with 120km G.652 (depending on the transceiver type) in any case. There are plenty of commercial solutions available for such spans, or he can try a building-block approach.
My point is to skip EDFAs in a single 1G 120km fiber setup for commercial aspects, let alone technical reasons (complexity, safety), if there is no requirement for more bandwidth. IMHO even with multiple 1G CWDM-style setups, but your mileage may of course vary.
You're also vastly exagerating the power of what are effectively metro
reach amps, you're really in no danger of making an eye hazard unless
you start slapping on ultra long-haul 1500+km transport gear with class
3B lasers
In Mikes scenario this might be as a +10dB pre-amp would do the trick with low power, but a post-amp (+17dB gain with levels around -20..-30dBm to get some additional power budget) is what I would use if EDFAs are a stringent requirement.
Most new long-haul transport systems have an automatic power-off feature for optical protection (e.g.the splice teams after a fiber cut/disconnect) now because of this.
> (i.e. you're in far more danger from someone with a green
laser pointer ordered from the Internet :P).
Agreed, but failed to save the whales - http://www.youtube.com/watch?v=Tuxf2xJ08Cc
Remember that 1550nm is
infrared and very effectively filtered by the human eye, so even a
+17dBm output EDFA (the max output for most metro systems) is still
going to be class 1M and effectively safe as long as you don't stare at
it in a microscope.
Or stare in the beam at 500mW/27dBm without noticing because it is infrared, and there is no eyelid closure reflex. I tend not to take chances for my colleagues and me but as common knowledge says it is everyones own decision to look into the laser with the remaining good eye.
Cheers,
.