Acousto-Optic Modulator for Emulating Atmospheric Fade in Free-Space Optical Communication Systems

This report presents our model for atmospheric turbulence fade for an Earth/Space system, and our physical emulation test bed components. For modeling the atmosphere, we have used the Hufnagel-Valley model, in combination with Cn(2) measurement parameters and MATLAB software. From these models, power fluctuation time series were generated and subsequently converted to voltages that were uploaded into an acousto-optic modulator and signal generator. The acousto-optic modulator is a compact, fiber-based device that has a maximum 55 MHz response and 45 dB of range, making it a viable component for future integration into a laboratory atmospheric emulation test bed. Results from our fade model implementation with the acousto-optic modulation system will be offered and discussed.