V.I. Voronov - Dr.Sc. (Eng.), Professor, Department of Electronic and Quantum Devices, Kazan National Research Technical University named after A.N.Tupolev E-mail: vvi_kai@mail.ru F.N. Nuramov - Post-graduate Student, Kazan National Research Technical University named after A.N. Tupolev E-mail: nuramoff@yandex.ru I.A. Al Taher - Master, Kazan National Research Technical University named after A.N.Tupolev E-mail: eenas.taher@gmail.com

The article considered the characteristics of the field in the far zone of the multi-fiber laser emitter for free space optics (FSO), containing in each optical fiber (OF) phase modulators, providing the required amplitude-phase distribution (AFD). Multi-fiber emitter operates similarly to phased array antenna (PAA) and may be used to compensate of the turbulent distortion of di-rectivity pattern caused by atmosphere as a main component of an adaptive optical system. The purpose of the work is evaluating the effect of inhomogeneity AFD of the radiation within the output aperture at misalignment of the primary source on the field in the far zone. The authors examined by the numerical simulation the effect of the angular misalignments of primary source relative to the splitter\'s input fiber on the work of multi-fiber emitter. The analysis was conducted by comparing the results obtained for the AFD in the far field of a single (single-fiber) and the multi-fiber emitters with the equal size of output apertures. According to the results, it can be concluded that the angular misalignments of the primary source of a single emitter lead to strong distortions of the directivity pattern and, as a result, to irregularity of the field in the far zone. At misalignment of the primary source more than 10 ang. min. in the far zone, the principal maximum can not be identified and separated from the secondary maximums that leads not only to difficulties in guidance, but also to a complete loss of information. In the case of a multi-fiber emitter when each fiber contributes to formation of the primary AFD, angular misalignment of the primary source should not have a strong influence on the structure of the field in the reception area of FSO.

 

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