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