Wavefront Compensation Technique for Terrestrial Line of Sight Free Space Optical Communication

Free Space Optical Communication (FSOC) refers to an optical communication where unguided visible, infrared or ultraviolet light is used to carry the signal. In Wireless Optical Communication systems, optical signal is modulated and transmitted over the free space atmospheric channel. When the laser beam is propagating through the turbulent atmospheric channel it is heavily affected by various parameters. Generally, the intensity of the laser beam is greatly degraded by the phenomenon such as absorption and scattering effect due to natural atmospheric components namely gases, dust, smoke, precipitation, fog, rain etc. In other hand, the performance of FSOC is heavily affected by the fluctuation in the atmosphere. This fluctuation results in atmospheric turbulence effect such as beam wandering beam scintillation and wavefront aberration. Therefore, the performance of the FSOC is degraded by the atmospheric turbulence tremendously. Hence it is necessary to develop a suitable optoelectronic arrangements and algorithms to compensate the atmospheric turbulences. This paper shows the viability to improve the performance of FSOC by compensating the atmospheric turbulence effect. In this paper, a wavefront aberration compensation technique to mitigate the wavefront aberrations due to the channel is developed using the necessary opto electronic assembly. This paper mainly elaborates experimental implementation for calculation of wavefront aberration and also demonstrates the correction achieved experimentally.