Interesting work, but 19 cores is very much not standard. Multiples of 12 cores are the gold standard in the telecommunications industry. Ribbon fibre is typically 12, sometimes 24 fibres per ribbon, and high count cables these days are 864 cores or more using a more flexible ribbon structure that improves density while still using standard tooling.
You're confusing multi-core in a single cladding with multiple strands of cladding. This is 19 cores in a single cladded 125µm (which is quite impressive manufacturing from Sumitomo).
I wasn't confusing anything. To interoperate with industry standard fibre optic cables it should have a multiple of 12 or 24 cores, not the complete oddball number of 19. Yes it's cool that it's that small, but that is not the limiting factor in the deployment of long haul fibre optic telecommunications networks.
Sumitomo sells a lot of fusion splicers at very high margins. It is in their best interest to introduce new types of fibre that requires customers to buy new and more expensive fusion splicers. Any fibre built in this way will need rotational alignment that the existing fusion splicers used in telecom do not do (they only align the cores horizontally, vertically and by the gap between the ends). Maybe they can build ribbon fibres that have the required alignment provided by the structure of the ribbon, but I think that is unlikely.
Given that it does not interoperate with any existing cables or splicers, the only place this kind of cable is likely to see deployment in the near term is in undersea cables where the cost of the glass is completely insignificant compared to everything that goes around it and the increased capacity is useful. Terrestrial telecom networks just aren't under the kind of pressure needed to justify the incompatibility with existing fibre optic cables. Data centers are another possibility when they can figure out how to produce the optics at a reasonable cost.
It's impossible for this to interoperate with "normal" fiber, this is "coupled-core" fiber: the cores don't operate independently and a MIMO style setup like the paper describes is really the only thing you can do.
Additionally, the setup uses optical amplifiers in 86.1km steps.
Both of these things put this squarely in submarine-cable-only space. Total cable size is in fact a problem in that space, 4-core claddings are roughly state of the art there, but there's enough room for those to be non-coupled. Higher core counts requires research like this.
Either way you'd be terminating a 19-core setup like this with an OEO (and probably FlexE and/or an OTN solution) both ends.
