How Laser Communication Works


Laser Communication Applications: From Outer Space to Wall Street

Laser communications may be a boon for space exploration, but far more earthly pursuits will determine its fate as a commercial technology.

Take, for example, Wall Street's emerging breed of high-speed traders who leverage the power of quantitative analysis, the speed of premium broadband and a multiplicity of microtransactions to pile up earnings one fractional penny at a time. For a business built on "robo-traders," computer algorithms making millisecond trades according to a set of rules, transmission time is money, and lasers are the fastest game in town [sources: Adler; CBS News; Strasburg].

To squeeze the most out of each trade, companies like Spread Networks invested in the best available fiber and cut every kink and curve they could from the data hoses connecting trade capitals like Chicago, New York, London and Tokyo (each extra mile adds about eight microseconds to data round-trips). When that wasn't fast enough, others groups, like McKay Brothers and Tradeworx, cast fiber optics aside in favor of microwaves beamed through the air. Though only a step above radio in terms of power and speed, microwaves travel faster through air than light passes through fiber optics [sources: Adler; Strasburg].

Lasers would potentially post the fastest speeds of all; the speed of light through air is nearly as fast as in a vacuum, and could traverse the 720 miles (1,160 kilometers) separating New York and Chicago in about 3.9 milliseconds -- a round-trip (aka latency) of 7.8 milliseconds, compared to 13.0-14.5 milliseconds for new fiber optic systems and 8.5-9.0 milliseconds for microwave transmitters [source: Adler].

In the security sphere, lasers and other optical communications systems offer more secure communications -- and the means to eavesdrop on them. Quantum cryptography takes advantage of a property of quantum physics -- namely, that a third party cannot detect the quantum state of the photonic encryption key without altering it and, therefore, being detected -- to establish highly secure communications using beams of photons created by attenuated lasers [sources: Grant; Waks et al.]. In fall of 2008, researchers in Vienna began experimenting with a quantum Internet based in part on this principle [source: Castelvecchi]. Unfortunately, lasers have also been used to intercept and spoof such signals in a non-quantum way, thereby circumventing detection. Quantum encryption companies are working to address the problem [sources: Dillow; Lydersen et al.].

In fact, the main drawbacks to laser communications within the atmosphere have to do with interference by rain, fog or pollutants, but given the technology's advantages, these issues are unlikely to stop the forward progress of the technology. So, literally or figuratively, the sky is the limit for laser communications technologies.

Author's Note: How Laser Communication Works

Laser communications are another great example of how we're living in the future, but I'll always associate the concept with an episode from the past. During the Cold War, Léon Theremin -- inventor of video interlacing as well as the namesake electric instrument heard in scores of science fiction films -- developed a light-based listening device capable of remotely bugging an office (it was actually a low-power infrared beam, not a laser). It worked by detecting the vibrations on a pane of glass caused by the sound pressure generated by voices within the target room. The Soviets used this device, the ancestor of modern laser microphones, to eavesdrop on various embassies in Moscow.

Related Articles

Sources

  • Adler, Jerry. "Raging Bulls: How Wall Street Got Addicted to Light-Speed Trading." Wired. Aug. 3, 2012. (Nov. 15, 2013) http://www.wired.com/business/2012/08/ff_wallstreet_trading/all/
  • Castelvecchi, Davide. "Welcome to the Quantum Internet." Science News. Aug. 16, 2008. (Nov. 15, 2013) https://www.sciencenews.org/node/21502
  • CBS News. "How Speed Traders are Changing Wall Street." June 5, 2011. (Nov. 15, 2013) http://www.cbsnews.com/8301-18560_162-20066899.html
  • Cowen, Rob. "Inventing the Light Fantastic." Science News. May 8, 2010. (Nov. 15, 2013) https://www.sciencenews.org/node/21675
  • Dillow, Clay. "Quantum Hackers Use Lasers to Crack Powerful Encryption Without Leaving a Trace." Popular Science. Aug. 30, 2010. (Nov. 15, 2013) http://www.popsci.com/technology/article/2010-08/quantum-hackers-use-lasers-crack-quantum-encryption-scheme-leaving-no-trace
  • Duarte, F. J. "Secure Interferometric Communications in Free Space." Optics Communications. Vol. 205, no. 4. Page 313. May 2002.
  • Duarte, F. J. et al. "N-slit interferometer for Secure Free-Space Optical Communications: 527 m Intra Interferometric Path Length." Journal of Optics. Vol. 13, no. 3. Feb. 3, 2011.
  • Grant, Andrew. "Quantum Cryptography Takes Flight." Science News. April 1, 2013. (Nov. 15, 2013) https://www.sciencenews.org/article/quantum-cryptography-takes-flight
  • Hadhazy, Adam. "How It Works: NASA's Experimental Laser Communication System." Popular Mechanics. Sept. 6, 2011. (Nov. 15, 2013) http://www.popularmechanics.com/science/space/nasa/how-it-works-nasas-experimental-laser-communication-system
  • Institute of Physics. "Case Study: Lasers." (Nov. 15, 2013) http://www.iop.org/cs/page_43644.html
  • Jones, Stacy V. "PATENTS; Lasers from Satellites a Link to Submarines." The New York Times. July 18, 1981. (Nov. 15, 2013) http://www.nytimes.com/1981/07/18/business/patents-lasers-from-satellites-a-link-to-submarines.html
  • Lydersen, Lars. "Hacking Commercial Quantum Cryptography Systems by Tailored Bright Illumination." Nature Photonics. Vol. 4. Page 686. 2010.
  • Markoff, John. "A Chip That Can Transfer Data Using Laser Light." The New York Times. Sept. 18, 2006. (Nov. 15, 2013) http://www.nytimes.com/2006/09/18/technology/18chip.html?_r=0
  • MIT News. "3Q: Don Boroson on NASA's Record-Breaking Use of Laser Communications." Oct. 28, 2013. (Nov. 15, 2013) http://web.mit.edu/newsoffice/2013/3q-don-boroson-1028.html
  • NASA. "LLCD Space Terminal." (Nov. 15, 2013) http://esc.gsfc.nasa.gov/267/271/Space-Terminal.html
  • NASA. "ASA Laser Communication System Sets Record with Data Transmissions to and from Moon." Oct. 22, 2013. (Nov. 15, 2013) http://www.nasa.gov/press/2013/october/nasa-laser-communication-system-sets-record-with-data-transmissions-to-and-from/#.UmlK6JyZAUU
  • National Geographic. "The Big Idea: How Breakthroughs of the Past Shape the Future." National Geographic. Sept. 6, 2011.
  • Science News Letter. "Laser Communications System Developed." Jan. 25, 1964.
  • Strasburg, Jenny. "On Your Mark, Get Set..." Wall Street Journal. Oct. 10, 2011. (Nov. 15, 2013) http://online.wsj.com/news/articles/SB10001424052970204524604576610860386189444
  • Thomsen, D. E. "A Pure Laser for Clean Communications." Science News. April 23, 1983.
  • Waks, Edo, et al. "Secure Communication: Quantum Cryptography with a Photon Turnstile." Nature. Vol. 420. Dec. 19, 2002.

More to Explore