An international team of researchers has developed a method of manipulating light beams made of "twisted" waves to transmit information at incredible speeds. With "twisted" light beams, wireless communication can be 85,000 times faster than broadband Internet speeds.
Researchers have clocked such light beams at speeds up to 2.56 terabits of data per second, roughly the equivalent of more than 66 DVDs worth of data in just one second. The breakthrough could allow military space satellites or NASA missions to transmit data at ultra-high speeds. The technique is based on the orbital angular momentum of the waves.
Recent work indicates the method could greatly boost the data-carrying capacity in optical fibers and Wi-Fi, and the demonstration of the approach will likely lead to even higher rates. When applied to light, angular momentum can be a rather slippery concept, but the Earth itself stands for a closer analogy. The Earth has "spin angular momentum" as it spins on its axis, and "orbital angular momentum" as it revolves around the Sun.
Light can have both types of angular momentum, but the spin version associated with polarization is more familiar. Many data-carrying applications using light pack more data on to light waves by encoding one polarization with one data stream, and another polarization with a different stream. This way, twice as much information can fit within the same range of colors processed by the transmitting equipment.
The international team of researchers from the University of Southern California (USC), China, Pakistan, and Israel, said the data transmission process they developed goes around the need for bandwidth, because the twists in the twisted laser beams "can effectively create the equivalent of a new data stream channel - similar to a radio having separate channels - without the need for more bandwidth," reported Innovation News Daily. "We didn't invent the twisting of light, but we took the concept and ramped it up to a terabit-per-second," Alan Willner, professor of electrical engineering at USC, told the site.
According to the abstract published in this week's issue of Nature Photonics, researchers used four light beams which were "multiplexed and demultiplexed" to ramp transmission speed up to 1.37Tbps. The scientists then deployed "two groups of concentric rings of eight polarization-multiplexed 20 x 4Gbit s-116-QAM-carrying orbital angular momentum beams" to ramp it up to 2.56Tbps.
Earth's atmosphere, however, allows beaming of data via twisted light only over very short distances, but it should work well in space. The Pentagon's Defense Advanced Research Projects Agency (DARPA) is reportedly testing twisted light as a method of communicating between satellites.
