APPLIED PHYSICS: Unscintillating Conversation

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Science  25 Jul 2008:
Vol. 321, Issue 5888, pp. 466d-467d
DOI: 10.1126/science.321.5888.466d

Air-to-air and air-to-ground communication are generally carried out with radiofrequency transmitters and receivers. By comparison, optical-based communication systems offer a number of advantages, including higher bandwidth and the capacity to communicate information at higher rates, bundled with low weight, compact size, low power requirements, and the added security of a direct line-of-sight communication channel. However, the air turbulence that makes stars twinkle or scintillate at a detector presents a substantial problem for airborne optical communication. Unchecked, such turbulence will introduce a large amount of error into a communication channel. As an alternative to the relatively large adaptive-optics approach that uses a reference beam to remove the twinkle from the stars with wavefront engineering, Louthain and Schmidt show that a multiple-transmitter approach using several optical beams can also work. Their numerical simulations take into account a number of factors such as beam separation, phase difference, and angle of propagation of the individual beams. By averaging out the contribution from turbulence-induced shifts they show that the multiple-beam approach can significantly reduce the bit-error rate in messages over the optical channel. — ISO

Opt. Express 16, 10769 (2008).

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