Twisted Light Leads to 2.56 Tb/s Link

Orbital angular momentum boosts bandwidth

1 min read

Scientist in California and Israel say they've transmitted data through the air at a rate of 2.56 terabits per second using beams of "twisted light."

Such light poses the quantum property orbital angular momentum. As Alexander Hellemans explained in our May issue:

A photon can carry angular momentum just as a rotating body does and can even transfer the momentum to small particles, causing them to rotate. In theory, a photon can occupy any one of an infinite number of these quantum states, each associated with an integer value. These quantum states impart the... beam with a distribution of phases as it travels through space that gives the beam the shape of fusilli pasta (a helix).

Beams with different orbital angular momentum can be transmitted together on the same beam and then distinguished from each other at a receiver as if they had been sent on separate channels.

The communications technology could find a home in  satellite communication links, in short free-space optical links on earth (such as between buildings in a city), or maybe in  fiber optic cables (which the engineers say is their next step).

Orbital angular momentum has been studied intensively at optical wavelengths, but recently physicists have been trying to apply it to radio frequencies. Scientists in Europe claimed the first twisted RF communications earlier this year. But others question whether twisted RF is really different from other multiple-input-multiple-output radio techniques.

The research was publish on 24 June in Nature Photonics. The research team included Jian Wang, Jeng-Yuan Yang, Irfan M. Fazal, Nisar Ahmed, Yan Yan, Hao Huang, Yongxiong Ren, Allan Willner, and Yang Yue from the University of Southern California; Samuel Dolinar from NASA's Jet Propulsion Laboratory; and Moshe Tur from Tel Aviv University.

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Why the Internet Needs the InterPlanetary File System

Peer-to-peer file sharing would make the Internet far more efficient

12 min read
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Carl De Torres

When the COVID-19 pandemic erupted in early 2020, the world made an unprecedented shift to remote work. As a precaution, some Internet providers scaled back service levels temporarily, although that probably wasn’t necessary for countries in Asia, Europe, and North America, which were generally able to cope with the surge in demand caused by people teleworking (and binge-watching Netflix). That’s because most of their networks were overprovisioned, with more capacity than they usually need. But in countries without the same level of investment in network infrastructure, the picture was less rosy: Internet service providers (ISPs) in South Africa and Venezuela, for instance, reported significant strain.

But is overprovisioning the only way to ensure resilience? We don’t think so. To understand the alternative approach we’re championing, though, you first need to recall how the Internet works.

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