Free space optical system design using particle swarm optimization

Summary The performance of the free‐space optical (FSO) communication system is severely affected by atmospheric properties and misalignment between transmitter‐receiver sections. These effects can be minimized by selecting the precise and proper value of operating parameters. The divergence angle can play a key role in mitigating the negative impact of deviation of an optical beam from its fundamental direction due to different adverse influences. In this paper, we have presented a particle swarm optimization model for determining the optimum divergence angle for designing an optimal FSO link. The FSO transreception quality depends on the medium properties which have a number of detrimental effects like rain, fog, haze, physical obstruction, scattering, and atmospheric turbulence. The proposed work investigate the optimum divergence angle with respect to the maximum deviation angle under different adverse conditions, as mentioned above. Taking into account these effects, the analytical expression of optical link margin and the optimum divergence angle with respect to the maximum deviation angle is derived. The results are analyzed for finding out the most suitable wavelength of the transmitter, transmitted power, link margin, and the link budget under different adverse conditions for reliable communication.