Li-Fi

Optical Computers Run At The Speed Of Light—Literally

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Virtually every device you use—from the one you’re using to read this to the pocket calculator growing dust in the back of your desk—relies on the same basic technology: circuits containing many tiny transistors that communicate with each other using electrons. We’ve come a very long way since the room-sized computers of the 1950s, but as computing gets smaller, faster, and more complicated, we get closer to hitting a wall. There’s a physical limit to how powerful traditional computers can get. That’s why scientists are turning to completely new forms of technology for future computers.

The first in our three-part series explored how some computers use artificial neurons to “think.” Discover another way scientists are rethinking computing in the second part of the series below.

Computing At The Speed Of Light

 Neurons are only one way to make computers more like brains. Another way is by changing the medium they use to communicate. Conventional computers exchange information in the form of electrons, while the human brain uses a complex mix of chemical signals. Some research suggests, however, that the brain also relies on light particles known as photons. What if computers did too?

Optical computing is designed to do just that. Photons can move information much more quickly than electrons can—they literally travel at the speed of light. We’re already using photons to send data at breakneck speeds via fiber-optic cables; the problem is that the data has to be converted back into electrons once it arrives at its destination. If you could replace a computer’s wires with optical waveguides, it might be able to do all the same things it could before at a much greater speed.

Photons Aren’t A Fix-All

 There are a few problems, though. For one thing, light waves are just too big for what we need them to do. According to ExtremeTech, “In general, the smallest useful wavelength of light for computing has been in the infrared range, around 1000 nm in size, while improvements in silicon transistors have seen them reach and even pass the 10 nm threshold.” There are a few tricks scientists can use to get around this problem, but they add unnecessary complications to something that needs near-flawless speed and precision.

Still, the principles of optical computing are useful in certain circumstances. Li-Fi uses light instead of radiowaves to broadcast wireless internet 100 times faster than Wi-Fi, for instance. Technologies such as Optalsys have also found novel ways to get around light’s limitations. In the future, your laptop may not run on photons, but optical computing will surely have a place.

Watch And Learn: Our Favorite Content About Optical Computing

Researchers Create A Light-Based Microprocessor

It’s up to 50 times faster than electron-based microprocessors.

A New Type of Li-Fi Has Reportedly Cracked 40 Gbps, 100 Times Faster Than the Best Wi-Fi

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We’re so ready.

If you’re frustrated with slow wi-fi, you might be one of the many people eagerly awaiting the commercialisation of li-fi (or light-based wi-fi), which promises to be up to 100 times faster than the connections we use today.

Most li-fi systems rely on transmitting data via LED bulbs, which means there are some limitations to how easily the technology could be applied to systems outside the lab. But researchers have come up with a new type of li-fi that uses infrared light instead, and it’s reportedly already cracked 40 gigabits per second (gbps) in early testing.

 For those who missed the li-fi hype, the communications system was first invented in 2011, based on the idea of transmitting data via the imperceptible flickering of LED light – think morse code happening so fast, it’s invisible to the human eye.

Lab-based tests have shown that this type of li-fi can achieve speeds of 224 gbps. In real-world testing back in 2015, that speed was slowed down to a still-impressive 1 gbps, getting people excited about the possibility of li-fi in their homes and offices – all you need is an LED bulb.

But there are some challenges with LED-based li-fi. Obviously, the fact that it requires a light to be turned on in order to work means you can forget lying in bed in the dark and scrolling through Facebook at breakneck download speeds).

And just like regular wi-fi, existing LED li-fi systems use one bulb to beam data to all connected devices, so it slows down the more devices that are connected to it.

To fix these issues, PhD student Joanne Oh from Eindhoven University of Technology in the Netherlands has taken the li-fi concept and run with it, creating a new type of system based on harmless infrared light, rather than LED.

Infrared li-fi isn’t a new idea, but most other experimental systems use energy-intensive movable mirrors to beam infrared light, so haven’t been very promising for commercialisation.

 Instead, Oh’s system uses passive antennae to send out the data, with no moving parts.

“This new concept won’t simply outstrip current WiFi speeds and provide interference-free connections. There are no moving parts here, making power requirements much lower,” Rob Lefebvre writes for Engadget.

According to an announcement made by Eindhoven University this week, early tests have already achieved a download speed of 42.8 gbps over a distance of 2.5 metres (8.2 feet) using the system.

To put that into perspective, the average connection speed for most people in the Netherlands is around 17.6 mbps (2,000 times slower), and the best wi-fi systems available max out at around 300 mbps (around 100 times slower).

The team is currently waiting for that 42.8 gbps speed to be published in a peer-reviewed journal, so we have to remain skeptical for now, but you can see earlier publications on the li-fi system here and here.

What we know right now is that the system works by beaming wireless data through a few central ‘light antennae’ that are mounted on the ceiling.

These antennae direct rays of infrared light supplied by an optical fibre using gratings that radiate rays light rays in different directions depending on their wavelengths and angles, which means they don’t require power or maintenance.

eindhovenwifiEindhoven University of Technology

Each device get its own ray of light at a slightly different wavelength, so the connection shouldn’t slow down, no matter how many smartphones and computers are using it at once.

The infrared light used by the systems is greater than 1,500 nanometres, which puts it in a frequency range of around 200 terahertz.

For comparison, wi-fi uses radio waves with a frequency of either 2.5 or 5 gigahertz, which have a lot more interference. And because the wavelengths of infrared light being used to transmit data can’t be detected by the cells in our retina, they’re invisible to our eyes.

The infrared li-fi hasn’t been tested for its upload speeds as yet – for now the system will use radio waves for uploads.

Oh’s project was part of a larger group working on the system at the uni – other projects are now investigating how these antennae can track online devices as they move around a space, so that the connection doesn’t get disrupted when people travel between rooms.

Head of the group, Ton Koonen, said in a press release that it’ll still be at least five years before the new technology could be commercialised, with the “first devices to be connected to this new kind of wireless network will be high data consumers like video monitors, laptops or tablets”.

However, there are still some hurdles to overcome, regardless which type of li-fi you’re looking into.

Even though infrared light can pass through more materials than visible light, both types of li-fi won’t be able to transmit through walls – which is great if you want to keep your connection super secure, but probably not that user-friendly.

There’s also the question of whether our devices are advanced enough to make use of such super-fast connections – data still has to be slowed down to be sent around our electricity-based devices.

But while researchers figure that out, it’s nice to know that there are now two promising li-fi systems being tested and improved all the time.

In science, competition is an awesome driver of innovation, and we’re looking forward to seeing which type of li-fi system hits the market first.

Source:http://www.sciencealert.com

The inventor of light-based ‘Li-Fi’ Internet has completed the first working prototype

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Back in 2011, during a TED Talk in Scotland, professor Harald Haas introduced a revolutionary ideato the world: what if a wireless Internet system could run on nothing but an LED lightbulb? Back then, this “Li-Fi” concept was just a cool idea, but now, roughly four years later, professor Haas is back with a working prototype. If this invention catches on, all you’ll need is a lightbulb and a solar cell to get online in the not-so-distant future.

Through a collaboration between the University of Edinburgh’s Li-FI R&D Centre and a university offshoot company called pureLiFi Ltd, the past four years have brought light-powered Internet connectivity out of the theoretical stage and into a tangible Li-Fi router. The real-world applications for Li-Fi connectivity could revolutionize the way much of the world gets online. The R&D team bringing Li-Fi to the real world expects that solar homes, consumer gadgets, and Internet of things devices will all be able to absorb power and receive data simultaneously with a Li-Fi system in place.

The Li-Fi prototype relies on solar energy to power Internet connections so that an LED light source paired with a solar panel becomes a fully functional transmitter and receiver system for high speed, secure data transfer. Instead of relying on hardwired cables or radio waves that are easily interrupted, Li-Fi uses the nearly undetectable flicker of an LED light to transmit data.

Li-Fi is much faster than most standard Wi-Fi connections, and, perhaps most importantly, provides a connection that is significantly more secure. Because Li-Fi relies on light to transmit data, you have to be in the room with your device and the Li-Fi router in order to get connected. That would preclude strangers or literal outsiders from piggy-backing on your connection or eavesdropping on your online activity.

Beyond the widespread Internet access that Li-Fi could help provide around the world, the technology also has applications for reliable systems like smart city networks and Internet of Things connectivity in the smart homes of the future.

“The wider opportunity is to transform global communications by speeding up the process of bringing Internet and other data communication functionality to remote and poorer regions in a way not previously thought achievable due to lack of infrastructure and investment,” said Tom Higgison, Edinburgh Research & Innovation’s IP Project Manager. Edinburgh Research & Innovation is the commercial branch of the technological developments accomplished on the University side, and they have announced they are looking for industrial partners to help bring Li-Fi routers to a more mainstream audience.

In future, the internet could come through your lightbulb

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The tungsten lightbulb has served well over the century or so since it was introduced, but its days are numbered now with the arrival of LED lighting, which consume a tenth of the power of incandescent bulbs and have a lifespan 30 times longer. Potential uses of LEDs are not limited to illumination: smart lighting products are emerging that can offer various additional features, including linking your laptop or smartphone to the internet. Move over Wi-Fi, Li-Fi is here.

Wireless communication with visible light is, in fact, not a new idea. Everyone knows about using smoke signals on a desert island to try to capture attention. Perhaps less well known is that in the time of Napoleon much of Europe was covered with optical telegraphs, otherwise known as the semaphore.

The photophone, with speech carried over reflected light.
Amédée Guillemin

Alexander Graham Bell, inventor of the telephone, actually regarded the photophone as his most important invention, a device that used a mirror to relay the vibrations caused by speech over a beam of light.

In the same way that interrupting (modulating) a plume of smoke can break it into parts that form an SOS message in Morse code, so visible light communications – Li-Fi – rapidly modulates the intensity of a light to encode data as binary zeros and ones. But this doesn’t mean that Li-Fi transceivers will flicker; the modulation will be too fast for the eye to see.

Wi-Fi vs Li-Fi

The enormous and growing user demand for wireless data is placing huge pressure on existing Wi-Fi technology, which uses the radio and microwave frequency spectrum. With exponential growth of mobile devices, by 2019 more than ten billion devices are expected to exchange around 35 quintillion (1018) bytes of information each month. This won’t be possible using existing wireless technology due to frequency congestion and electromagnetic interference. The problem is most acutely felt in public spaces in urban areas, where many users try to share the limited capacity available from Wi-Fi transmitters or mobile phone network cell towers.

A fundamental communications principle is that the maximum data transfer possible scales with the electromagnetic frequency bandwidth available. The radio frequency spectrum is heavily used and regulated, and there just isn’t enough additional space to satisfy the growth in demand. So Li-Fi has the potential to replace radio and microwave frequency Wi-Fi.

Light frequencies on the electromagnetic spectrum are underused, while to either side is congested.

Visible light spectrum has huge, unused and unregulated capacity for communications. The light from LEDs can be modulated very quickly: data rates as high as 3.5Gb/s using a single blue LED or 1.7Gb/s with white light have been demonstrated by researchers in our EPSRC-funded Ultra-Parallel Visible Light Communications programme.

Unlike Wi-Fi transmitters, optical communications are well-confined inside the walls of a room. This confinement might seem to be a limitation for Li-Fi, but it offers the key advantage that it is very secure: if the curtains are drawn then nobody outside the room can eavesdrop. An array of light sources in the ceiling could send different signals to different users. The transmitter power can be localised, more efficiently used and won’t interfere with adjacent Li-Fi sources. Indeed the lack of radio frequency interference is another advantage over Wi-Fi. Visible light communications is intrinsically safe, and could end the need for travellers to switch devices to flight mode.

A further advantage of Li-Fi is that it can use existing power lines as LED lighting so no new infrastructure is needed.

How a Li-Fi network would work.
Boston University

Lightening the burden of the internet of things

The internet of things is an ambitious vision of a hyper-connected world of objects autonomously communicating with each other. For example, your fridge might inform your smartphone that you have run out of milk, and even order it for you. Sensors in your car will directly alert you though your smartphone that your tyres are too worn or have low pressure.

Given the number of “things” that can be fitted with sensors and controllers then network-enabled and connected, the bandwidth needed for all these devices to communicate is vast. Industry monitor Gartner predicts that 25 billion such deviceswill be connected by 2020, but given that most of this information needs only to be transferred a short distance, Li-Fi is an attractive – and perhaps the only – solution to making this a reality.

Several companies are already offering products for visible light communications. The Li-1st from PureLiFi, based in Edinburgh, offers a simple plug-and-play solution for secure wireless point-to-point internet access with a capacity of 11.5 Mbps – comparable to first generation Wi-Fi. Another is Oledcomm from France, which exploits the safe, non-radio frequency nature of Li-Fi with installations in hospitals.

There are still many technological challenges to tackle but already the first steps have been taken to make Li-Fi a reality. In the future your light switch will turn on much more than just illumination.

Li-Fi to replace Wi-Fi in China?

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Chinese scientists have successfully developed a new cheaper way of getting connected to internet by using signals sent through light bulbs instead of radio frequencies as in Wi-Fi, a move expected to radically change process of online connectivity.

Four computers can be connected to internet through one- watt LED bulb using light as a carrier instead of traditional radio frequencies, as in Wi-Fi, said Chi Nan, an information technology professor with Shanghai‘s Fudan University.

Under the new discovery dubbed as ‘Li-Fi‘, a light bulb with embedded microchips can produce data rates as fast as 150 megabits per second, which is speedier than the average broadband connection in China, said Chi, who leads a Li-Fi research team including scientists from the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences.

The term Li-Fi was coined by Harald Haas from the University of Edinburgh in the UK and refers to a type of visible light communication technology that delivers a networked, mobile, high-speed communication solution in a similar manner as Wi-Fi.

With Li-Fi cost-effective as well as efficient, netizens should be excited to view 10 sample Li-Fi kits that will be on display at the China International Industry Fair that will kick off on November 5 in Shanghai.

The current wireless signal transmission equipment is expensive and low in efficiency, Chi said.

“As for cell phones, millions of base stations have been established around the world to strengthen the signal but most of the energy is consumed on their cooling systems,” she said.

“The energy utilisation rate is only 5 per cent,” state-run Xinhua news agency quoted her as saying.

Li-Fi was touted as a boon to China netizen community, the highest in the world with about 600 million connections.

Compared with base stations, the number of light bulbs that can be used is practically limitless.

Meanwhile, Chinese people are replacing the old-fashioned incandescent bulbs with LED light bulbs at a fast pace.

“Wherever there is an LED light bulb, there is an internet signal. Turn off the light and there is no signal,” Chi said.

However, there is still a long way to go to make Li-Fi a commercial success.

“If the light is blocked, then the signal will be cut off,” Chi said.

More importantly, according to the scientist, the development of a series of key related pieces of technology, including light communication controls as well as microchip design and manufacturing, is still in an experimental period.