> Research into OAM has suggested that light waves could carry hitherto unprecedented quantities of data through optical fibres. According to preliminary tests, data streams travelling along a beam of light split into 8 different circular polarities have demonstrated the capacity to transfer up to 2.5 terabits of data (equivalent to 66 DVDs or 320 gigabytes) per second.[40]
Note that we could already theoretically pack data into separate spatial modes (c.f. [0]), but the problem is in a real fiber, energy will leak from one mode into another, limiting useful signal. Compounding this is that different modes can propagate at different velocities, so you can e.g. have energy leak from mode A to B, travel more slowly for a moment, then back from B to A, which effectively smears your A signal even if you filter on the ends. This is why single mode fiber (i.e. fiber thin enough that only the single 00 mode fits) is used for high data rates/long distances. The same thing can happen with polarization modes, which you can't eliminate by just making your fiber smaller, so IIRC they are actually the enemy. So there are real engineering challenges to actually make extra channels be useful rather than harmful (this is all recollection of uni courses 15 years ago, but it seems single mode fiber has only become more popular, so I suppose it's still an issue).
I swear these random Wikipedia articles posted on HN now and then is like aliens/time travelers nudging us towards higher technology :)
I have never been able to understand light and I probably never will. Electromagnetism in general. Like actually wrap by head around and grok it intuitively
lioeters 53 minutes ago [-]
I suspect that feeling you have is because collectively we don't yet fully understand what light is. That's why theories about it are still not as elegant and simple as the material phenomenon is in its esssence.
About visitors from the future or an extraterrestrial civilization dropping subtle hints in our field of consciousness to nudge us all toward higher technology - there's an immense space of unimaginable possibility that we probably wouldn't even notice what happened until we reach the next level of that transformation and evolution, and reflect on how we got there.
Razengan 26 minutes ago [-]
> reflect on how we got there.
I'd say the breakneck speed of progress in the last 100 years.. in just like a 0.0001% of humanity's total history.. is pretty sus tbh :)
lioeters 3 minutes ago [-]
From the first barely flying airplane to rockets and satellites, from formalizing mathematical logic and figuring out basic physics to harnessing nuclear energy, building a world full of computers, robots and artificial intelligence. That leap is a blink of an eye in the scale of time, like snapping your fingers and shazam! The planet awakens.
https://gwern.net/doc/ai/1997-thompson.pdf
> [40] https://www.bbc.co.uk/news/science-environment-18551284
Fun!
[0] https://en.wikipedia.org/wiki/File:Intensity_profiles_of_Lag...
Spin angular momentum of light (SAM). https://en.wikipedia.org/wiki/Spin_angular_momentum_of_light
Angular momentum of light (with nice video) https://en.wikipedia.org/wiki/Angular_momentum_of_light
I have never been able to understand light and I probably never will. Electromagnetism in general. Like actually wrap by head around and grok it intuitively
About visitors from the future or an extraterrestrial civilization dropping subtle hints in our field of consciousness to nudge us all toward higher technology - there's an immense space of unimaginable possibility that we probably wouldn't even notice what happened until we reach the next level of that transformation and evolution, and reflect on how we got there.
I'd say the breakneck speed of progress in the last 100 years.. in just like a 0.0001% of humanity's total history.. is pretty sus tbh :)