Influence of random fluctuations of laser beam propagation direction on FSO power design

An algorithm for power design of ground-to-ground Free-Space Laser Communication Systems (Free-Space Optics (FSO)) is suggested. The random fluctuations of laser beam propagation direction, caused by mechanical vibrations of transmitter´s antenna and atmospheric turbulence, and also atmospheric extinction are taken into consideration. The algorithm allows calculation of laser source power and receiver´s antenna radius and transparency when the Bit-Error-Rate (BER) and the parameters that describe communication channel status are given. The analysis shows the FSO power design problem has no solution for desired BER when the mechanical vibrations and/or the atmospheric turbulence are strong enough. Influence of the initial radius of laser beam and random fluctuations of laser beam propagation direction on possible solutions of FSO power design problem are also studied. Suggested algorithm is used to analyze atmospheric turbulence and mechanical vibrations effect on the FSO power design for different communication channel lengths.