I thought the point of fibre was that it was low noise ... EDIT There's a good discussion of what you're talking about here [0] Upon further reading, there's

I thought the point of fibre was that it was low noise ... EDIT There's a good discussion of what you're talking about here [0] Upon further reading, there's a such thing as an all optical regenerator which would appear to provide the best of both worlds, though there's nothing here about how widely these are used [1] [0] http://www.rfwireless-world.com/Terminology/Optical-Repeater-vs-Optical-Amplifier.html http://www.rfwireless-world.com/Terminology/Optical-Repeater... [1] https://en.wikipedia.org/wiki/Mamyshev_2R_regenerator https://en.wikipedia.org/wiki/Mamyshev_2R_regenerator