Uploaded September 2022 | Updated September 2026, 3 weeks ago

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Undersea fiber optical cables connecting the continents contain periodically spaced amplifiers. But why don't we just put all the amplifiers on dry land at the other end or launch so much power that we still have plenty to spare when the signal arrives?

EDFAs explained:
rp-photonics.com/erbium_doped_fiber_amplifiers.html