18 April 2005 Evaluation of optical up- and downlinks from high altitude platforms using IM/DD
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The advantages of optical links like small, light and power efficient terminals are practical for high data rate services over high altitude platforms (HAPs). However, atmospheric effects can disturb the optical links and must be considered in link design. In this paper we evaluate clear sky and non clear sky attenuation effects and their impact on the link-quality of up- and downlinks from HAPs. As vertical links could be restricted by very large cloud and fog attenuation, investigations of the scattering effects in cloud media has been done. The Mie-theory shows that cloud transmittance is not depending on the wavelength, whereas the attenuation of fog and dust is smaller for longer wavelengths. Satellite cloud data has been used to predict the link availability for a ground station in Germany. A ground station diversity concept is introduced to achieve higher link availability. As high receiver sensitivity helps to reduce terminal mass, power and size, evaluation of receiver sensitivity is shown. Also, a receiver model is developed which enables to calculate for the background light loss in direct detection systems.
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Hennes Henniger, Hennes Henniger, Dirk Giggenbach, Dirk Giggenbach, Joachim Horwath, Joachim Horwath, Christoph Rapp, Christoph Rapp, } "Evaluation of optical up- and downlinks from high altitude platforms using IM/DD", Proc. SPIE 5712, Free-Space Laser Communication Technologies XVII, (18 April 2005); doi: 10.1117/12.600803; https://doi.org/10.1117/12.600803


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