Facebook Moves One Step Closer to Light-Based Wireless Communication

Jul 21, 2016

By Steph Yin

The internet is often called the “World Wide Web,” but it’s not actually accessible to residents of a large portion of the world. Today, four billion people are offline, and 1.6 billion of them live in sparsely populated areas around the world.

In recent years, a race to solve that problem has emerged among big tech companies like Google, SpaceX and Facebook. Now, Facebook has published research on an unconventional solution: using light to wirelessly transmit internet signals. The work comes from a Facebook-led initiative called Internet.org, which, according to the initiative’s website, has so far brought internet access to more than 25 million people.

Most internet signals today are transmitted at high rates through wired optical fiber networks — which require expensive infrastructure — or at lower rates through wireless radio frequencies, which are limited in bandwidth, subject to regulations and vulnerable to interception.

In a paper published Tuesday in Optica, researchers from Internet.org’s Connectivity Lab have outlined a new type of light detector that can be used for free-space optical communication, a communication technique that uses light to send data wirelessly.

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3 comments on “Facebook Moves One Step Closer to Light-Based Wireless Communication

  • This sounds similar to using microwave transmission. It sounds like light goes longer distance. With microwaves, different atmospheric conditions bend the waves, sometimes so badly they miss both collectors. The article did not talk about light’s immunity to this problem.

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  • Lasers make great satellite coms devices because

    1) they can be focussed into a very low divergence beam (an order of magnitude narrower than radio, dropping power and cost by two orders of magnitude. Power up in space is very expensive to deploy….though free to run from solar panels.

    2) Laser conversion efficiency is over 50% whilst RF transmitters are possibly only 20% at gigahertz frequencies (more power and cost saving (less power)

    Their downside is clouds.

    The receiver end is what this announcement is all about, turning a directional satellite light source captured it seems by quantum dots in or around optical fibres formed into the little birdcage/sphere. These directional photons are selectively captured (because of their wavelength) by correct nano-sized photonic features and re-emitted at longer wavelengths (almost instantly) into the fibre where they are fed to fast light sensors like Silicon PiN photodiodes or Silicon/Germanium avalanche photodiodes. (Silicon detectors are particularly good at green wavelengths.)

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