In the context of the increasing demand in high-speed data link for scientific, planetary exploration and earth observation
missions, the Italian Space Agency (ASI), involving Thales Alenia Space as prime, the Polytechnic of Turin and other
Italian partners, is developing a program for feasibility demonstration of optical communication system with the goal of
a prototype flight mission in the next future.
We have designed and analyzed a ground level bidirectional Free Space Optical Communication (FSOC) Breadboard at
2.5Gbit/s working at 1550nm as an emulator of slant path link. The breadboard is full-working and we tested it back-toback,
at 500m and 2.3km during one month. The distances were chosen in order to get an equivalent slant path
cumulative turbulence in a ground level link. The measurements campaign was done during the day and the night time
and under several weather conditions, from sunny, rainy or windy. So we could work under very different turbulence
conditions from weak to strong turbulence. We measured the scintillation both, on-axis and off-axis by introducing
known misalignments at the terminals, transmission losses at both path lengths and BER at both receivers. We present
simulations results considering slant and ground level links, where we took into account the atmospheric effects;
scintillation, beam spread, beam wander and fade probability, and comparing them with the ground level experimental
results, we find a good agreement between them. Finally we discuss the results obtained in the experimentation and in
the flight mission simulations in order to apply our experimental results in the next project phases.