That's very cool, but the "submarine communications cable" article I linked to above claims that the repeaters are powered by DC fed through a single conductor in the middle of the cable, though it doesn't cite a source for that information.
I wouldn't be surprised if both methods have been used in different situations or at different times.
Are you saying that there's an extra "pumping fiber" in the bundle, fed by a pumping laser on shore? Or are the pumping lasers in the repeaters, in which case there would still need to be electrical power supplied down the cable to drive the pumping lasers?
The DC may be likely for old-style repeaters, as Er-doped fiber amplifiers are (relatively) new.
It's my understanding that the pumping laser would be a different wavelength carried by the same fiber (just as a fiber can carry multiple data channels using different wavelengths in DWDM). The boost happens because of the special doped section.
The pumping laser essentially puts the doped medium in an energy condition where the data transmission can stimulate additional emission (similar to how lasers work in the first place). Few photons in, many out. The energy required to do so comes from the pumping laser.
I wouldn't be surprised if both methods have been used in different situations or at different times.
Are you saying that there's an extra "pumping fiber" in the bundle, fed by a pumping laser on shore? Or are the pumping lasers in the repeaters, in which case there would still need to be electrical power supplied down the cable to drive the pumping lasers?