4 ms·

> This means a theoretically infinite number of vortex beams can get overlaid on top of each other to carry an unlimited number of data streams at the same time

• javajosh 6y ago
  Another way to think of fiber optics is to imagine the analog case, like pumping a movie through the fibers. From there you can go in two directions, one making the channel machine readable, and the other increasing throughput. For machine readability you get something like a fast succession of QR codes. Throughput is, I think, more interesting because it turns out you can overlay 2 movies on each other! You can see this in various 3D movie technologies. Two channels are combined, and then separated by your glasses. The separation can happen by frequency (classic red/blue, a) or by polarization (the more modern style). NOW, apparently, there's a whole new way to distinguish the movies: angular momentum! Each physically differentiable thing gets you, very roughly speaking, one additional movie. So now you can pump 4 movies in one. Of course, it turns out you can split up each channel into smaller slices than 2, e.g. you could put up 2 distinct 3D movies if half the audience has red/blue and the other half orange and purple (would those colors work?) Frequency really is the big one, since light extends well outside the visible range, in both directions - your radio tunes by putting on very finely differentiated light filter (although really a reverse light filter in the sense that it only lets one very narrow set of frequencies in, rather than only keeping one narrow set of frequencies out).