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20 October 2004 A new approach for FSO communication and sensing
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Atmospheric effects can be devastating in FSO (Free Space Optics). The major ones are scintillation and beam wander. Often acquisition and tracking of the source is extremely difficult as well. Active optics is widely used to combat this problem. Passive optics using a modulated retrofreflector has proved much easier and possibly more effective, but the double pass through the atmosphere effectively doubles the attenuation coefficient, making it less attractive for long distances. We suggest here a system with the best features of both - one-way path with passive compensation. It uses a special, large, low-cost reflective diffuser screen with designer choice of illumination geometry and viewing direction and field of view. Essentially 100% of the incident light is scattered diffusely into that field of view. The limitations this poses on signal bandwidth and the advantages it offers in terms of acquisition, scintillation, beam wander, radiometric efficiency are discussed.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
H. John Caulfield "A new approach for FSO communication and sensing", Proc. SPIE 5550, Free-Space Laser Communications IV, (20 October 2004);

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