In today’s Academic Minute, Dr. Alan Willner of the University of Southern California reveals how twisting light could drastically increase data transmission speeds.
Alan Willner is a professor of electrical engineering and the Steven and Kathryn Sample Chair in Engineering at the University of Southern California. His research is focused on high-speed optical fiber communication systems, with emphasis on optical amplification and wavelength-division-multiplexed technologies and networks. He holds a Ph.D. in electrical engineering from Columbia University.
Dr. Alan Willner – Faster Data Transmission
People send more and more data every day, and much of this data is transmitted using light. In the 1990s, scientists discovered that light can have a property known as “orbital angular momentum.” A beam of light that carries digital data can twist in a helix as it moves through space.
The fascinating thing is that there can be many different rates of twisting for a beam. This property allows us to combine many data-carrying beams of differently twisted light. These beams actually occupy the same space but can be efficiently separated at a receiver. By doing so, we can increase the data capacity that is occupying the same space.
Recently, we transmitted data over open space in a lab at a rate of up to 2.5 terabits per second using multiple beams of light that were each twisted into a different helix. Each beam acted as an independent data stream – much like separate channels on your radio.
To put that in layman’s terms, the broadband cable that you probably use to check your email supports up to about 30 megabits per second. Our twisted-light system transmits more than 85,000 times as much data per second. While we didn’t invent the twisting of light, we took the concept and ramped it up to the terabit-per-second level.