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Proceedings Paper

Retro-reflective communications over a kilometre range using a MEMS-based optical tag
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Paper Abstract

We report on a laser communications experiment over a kilometre optical range where we have used a retro-reflective transponder incorporating an optical modulator based on silicon micro-electro-mechanical systems (MEMS) device. This employs interference to provide modulation and relies on performing as a coherent array to modulate incident light in the near-IR band (1550nm) over a wide angular range (120 degrees). Modulation is achieved by tuning a large array of Fabry-Perot cavities via the application of an electrostatic force to adjust the gap between a moveable mirror and the underlying silicon substrate. The micro-mirrors have a strong mechanical resonance, and modulate light by adjusting the spacing between the micromirrors and the substrate. We use a 'release and catch' technique to exploit the mechanical resonance, and we time the motion of the micro-mirrors to be synchronised with the arrival of an interrogator pulse to ensure that the etalon spacing provides the required modulation, whatever the angle of incidence. We describe experiments over a one kilometre path where simple strings were sent at 200kbit per second. We also discuss approaches to adapting the link to a given angle of incidence.

Paper Details

Date Published: 25 September 2009
PDF: 10 pages
Proc. SPIE 7480, Unmanned/Unattended Sensors and Sensor Networks VI, 74800L (25 September 2009); doi: 10.1117/12.835073
Show Author Affiliations
Andrew M. Scott, QinetiQ Ltd. (United Kingdom)
Kevin D. Ridley, QinetiQ Ltd. (United Kingdom)
David C. Jones, QinetiQ Ltd. (United Kingdom)
Mark E. McNie, QinetiQ Ltd. (United Kingdom)
Gilbert W. Smith, QinetiQ Ltd. (United Kingdom)
Kevin M. Brunson, QinetiQ Ltd. (United Kingdom)
Andrew Lewin, QinetiQ Ltd. (United Kingdom)
Keith L. Lewis, QinetiQ Ltd. (United Kingdom)


Published in SPIE Proceedings Vol. 7480:
Unmanned/Unattended Sensors and Sensor Networks VI
Edward M. Carapezza, Editor(s)

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