> If you’re using fiber optic cables, that’s 5-10k pairs, in 32U.

not with 4 or 12 core MCF!

Fair! Would still be a nightmare to manage, though. I wish they had some details on the proposed alternative waveguide.

I think the alternative is shown in figure 2. SiN (silicon nitride) is different from optical fiber. Both versions shown in figure 2 lack detail, especially in the small boxes labeled GC, Mirror, and PD. Depending on the details, one might put micro optical assemblies between or in those boxes in the figure. In any case, SiN waveguides are small, so you can pack many lanes in a small space.

MCF has a bunch of challenges, eg no good pigtail connector, need for rotational alignment, inability to radix (MCF is great for point to point, less good if you want to fan out from one chip to multiple chips), etc

And then even after all that, it’s still 1-2 orders of magnitude lower density than waveguides