
Corkscrew light promises higher optical-communication data rates - signa11
https://arstechnica.com/science/2020/05/corkscrew-light-promises-higher-optical-communication-data-rates/
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peter_d_sherman
Related:

[https://science.sciencemag.org/content/368/6492/760](https://science.sciencemag.org/content/368/6492/760)

>"Optical vortices on demand Light has _several degrees of freedom_
(wavelength, polarization, pulse length, and so on) that can be used to encode
information. A light beam or pulse can also be structured to have the property
of orbital angular momentum, becoming a vortex. Because the winding number of
the vortex can be arbitrary, the channel capacity can be expanded
considerably. Zhang et al. and Ji et al. developed nanophotonic-based methods
for generating and electrically detecting light with arbitrary orbital angular
momentum, a goal that has remained an outstanding challenge so far (see the
Perspective by Ge)."

[...]

"By harnessing the properties of total momentum conservation, spin-orbit
interaction, and optical non-Hermitian symmetry breaking, we demonstrate an
OAM-tunable vortex microlaser, providing chiral light states of variable
topological charges at a single telecommunication wavelength. The scheme of
the non–Hermitian-controlled chiral light emission at room temperature can be
further scaled up for simultaneous multivortex emissions in a flexible
manner."

Opinion: If Physics needs its own grand unified theory, then certainly Light
-- needs its own...

A careful codification of all of the properties of light and these properties'
mathematical relationships with one another -- would be one heck of a starting
step towards that eventual goal...

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hinkley
I remember reading an article about circular polarization in fiber optics ages
ago. They made it sound like it was just around the corner.

The fly in the ointment as I recall was that circular polarization required
some additional quality gates for the physical fiber that most fiber doesn't
meet. So while a lot of new fiber equipment has reused existing cable runs,
this would likely require new fiber to be laid.

What happened?

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RantyDave
IANA optical communications engineer, but this seems kinda wrong. Saying a
radio wave is at 500KHz with a bandwidth of 5KHz does not imply any level of
spectral efficiency unless I greatly misunderstand spectral efficiency.
Discuss?

~~~
itcrowd
Indeed, you are correct. Spectral efficiency is, essentially, how "well" those
5 kHz are being used. It doesn't have anything to do with the center frequency
(500 kHz in this example).

