Reading Exercise 7
Read the passage and choose the best answer to each question.
Laser-Beaming the Internet of the Future
Several tech companies are looking at laser or a combination of radio and laser technologies to take Internet connectivity the next level. Spearheading the effort are Google and Facebook. Google, which is deploying helium balloons in the stratosphere to provide Internet connectivity in remote areas as part of Project Loon, wants to use radio or laser to enable its balloons to transfer data in areas that are far from ground relay stations. Facebook wants to launch drones that use laser beams for high-speed Internet connectivity in remote regions. The idea is that the drone closest to urban areas would use laser to connect to the Internet and then pass along the connection to drones flying over rural areas.
“Both Google and Facebook think that if they can operate these aircraft in the stratosphere, roughly 20 kilometers above the Earth, they could kind of function like aerial cell towers and spread the connections more easily and without having to figure out the power and the cabling and everything on the ground," said Tom Simonite - the San Francisco Bureau Chief of the MIT Tech Review.
Facebook, in particular, is very interested in using laser to transfer data. “They claim to have set a new record and made the fastest laser data transfer ever," said Simonite. “And I just think it shows that they are taking it seriously and are trying to push the technology forward."
Other companies are coupling laser technology with radio redundancy to deliver uninterrupted Internet connectivity in inclement weather. In that kind of situation, Simonite said both laser and radio connections run in parallel, so that the laser can pick up any slack in case of radio interference. “They’re extremely fast," he said, “but if anything gets in the path of the beam, the signal is blocked." If the laser cannot travel in a straight line, the radio side would cover the deficit. “So it’s like a redundancy thing so that they always have a connection that’s live," he said. But the need to use both radio and laser simultaneously can be limiting, said Simonite. He said “lasers can be used to fuller potential" with project like the ones Google and Facebook are undertaking.
Light emitted by lasers can be modulated at very high speeds and can carry more than a petabit of data per second. A petabit is 1,000 terabits. A terabit equals a mind-boggling one trillion bits. The average U.S. Internet connection speed topped 11.7 megabits per second in the last quarter of this year, according to Akamai’s State of the Internet Report.
The technology is promising for developing countries and in parts of the world where laying cables is difficult, where cables are easily damaged, or in rural areas where labor and materials tend to be expensive. Simonite said governments and cellular carriers now want to push their coverage into new, unsaturated regions. “And it looks like this technology could help maybe with that in places where the regular way of connecting up cell towers with cables and so on doesn’t really work so well," added Simonite.
Laser technology is not new, however. Professor Siddharth Ramachandran of Boston University’s Nanostructured Fibers & Nonlinear Optics Lab, said laser, a critical feature of Internet connectivity, has been used for communications since the late 1970s. One company, in particular - Washington-based TeraBeam - was interested in the idea of free-space laser communications back in 2004 and produced free-space optical transceivers for Internet access.
Ramachandran speculated TeraBeam wanted to use 1550nm laser light, which is considered “eye-safe." It is unclear, however, if it is hazardous when used at higher levels of power in free-space communications. “The main reason I believe Terabeam planned to use 1550nm light is because most of the terrestrial and undersea fiber-optic communications equipment operates at this wavelength, which means it would be cheaper to piggy back on a lot of the technological infrastructure that was already developed," he said. “And while modern communications systems, [such as, for example Cable Television applications] transmit a lot of laser power through the fibers or devices in the system, the laser beam seldom exits packaged devices so as to be directly harmful to human beings," he said. Moreover, Ramachandran said laser beams connecting consumers with fiber-to-the-home applications “that promise massive bandwidths to each user, are low enough in power to not be a health concern generally." Propagating light in free space to wirelessly transmit data has the same advantages as wireless or satellite links, but will be more expensive. But Ramachandran said the costs could drop if the market is looking for the kind of higher bandwidth that laser-based free-space communications will provide.
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