Comment by eqvinox

I think the scaling parameters are a bit different here since the primary concern is the DSP power processing and correlating for MIMO 19 signals simultaneously. But the 16W figure for a 120km 400Gbps module includes a high-powered¹ transmitter amplifier & laser, as well as receive amplifiers on top of the DSP. My estimate is based on O(n²) scaling for 19×19 MIMO (=361) and then assuming 2≈3W of DSP power per unit factor.

[but now that I think about it… I think my estimate is indeed too low; I was assuming commonplace transceivers for the unit factor, i.e. ≤1Tb; but a petabit on 19 cores is still 53Tb per core…]

¹ note the setup in this paper has separate amplifiers in 86.1km steps, so the transmitter doesn't need to be particularly high powered.