Erbium Doped Fiber Amplifiers (EDFAs) do not re-shape or re-time the signals (the last 2 R's in 3R -- re-amplification, re-shaping, and re-timing)....
Thanks Chris - even more reading to do :) It's interesting stuff that's for sure. This is also pretty cool: http://en.wikipedia.org/wiki/Chirped-pulse_amplification I just had a thought about EFDA - please forgive my lack of terminology though, i'll try to explain: Say you have signal coming in to EFDA, the signal is just amplified (as you said, also noise - the whole source signal). Would it be possible to extract via PLL or similar the source clock and use that to modulate the amplifier power? Does it work with QPSK / whatever keying is used? Would that even help with the noise issue at all, or am I waaaaay off? Cheers