> OK, but can you really call "one" fiber with "multiple" cores a "single" optical fiber? Depends on what they actually used. There are special optical fibers

> OK, but can you really call "one" fiber with "multiple" cores a "single" optical fiber? Depends on what they actually used. There are special optical fibers with air holes (google for "photonic crystal fibers"), if they produces such fibers to guide multiple modes independently, you can really call it a single fiber. If they used separate fibers within a single plastic cladding, you can argue about that. If they used multiple fibers separate plastic claddings, they probably would have been shouted down at the conference where they presented their results :-)