Submarine cable systems often employ repeaters (hardened EDFAs). I remember one vendor bragging that not one of their units had EVER failed in service.
That PDF is great, thanks. Jesus - they are huge. Earlier in the PDF, they appear small.
Is that a single strand they are amplifying with these? I'd like to find cost figures for how much it is to run a single fiber trans-oceanically (if thats a word).
They talk about it in the PDF. Apparently they use a 1400nm laser along the same fiber that excites some receptor, which provides the power for the amplification.
If you want to see what they look like: http://www.nec.com/en/global/prod/nw/submarine/product/ns-se...