Correct. Modulation is encoding the bits in different aspects of the light wave. The better the modulation scheme, the more expensive is the division multiplexing equipment.
Not really. I know of no cases where optical amplifiers posed a barrier to upgrading. Ciena and Infinera have been able to upgrade cable capacity by several X.
Optical amplifiers simply boost the signal. A photo is absorbed and then re-emitted with more power, but the same frequency and phase.
There is no optical/electrical/optical conversion.
The throughput can be dramatically increased by upgrading the DWDM kit. The optical amplifiers in the water are technologically agnostic. The fibre can be a gating factor. For a while fibre with chromatic dispersion compensation was used and that actually limits the ability to upgrade the cable using modern coherent optics.
The article is accurate. I am the author. My sources are/were involved in designing the cable.
As noted the cable connects the US East Coast to South Africa and then heads to India and continues on to Australia before the home stretch to the States. We even know the number of fibre pairs, 16. It is a spatial division multiplexing system.
I am the author. The article is not speculation. I know from sources inside Facebook that the cable will head Southeast from the US East Coast directly to South Africa. From there it heads directly to India. From India to Australia. From Australia to the US West.
What is speculation are the branching units. It is natural to add branching units to aggregate traffic to more countries. But I have no confirmation.
