en تخصصي Special پژوهشي Research <p style="margin: 0in 0in 0pt; text-align: justify;">In this paper propagation of combined laser beam through atmosphere is investigated. Laser beam is combined via lens array arrangement. Turbulence is considered as an affecting factor of atmosphere and its effects on transverse coherence length (Fried parameter), peak intensity, propagation efficiency, and spot size of the laser beam is investigated. Coherent and incoherent combined beam are compared. It was seen that irrespective of laser beam quality in weak and medium turbulence levels, propagation efficiency parameter in coherent and incoherent beam combining has almost the same values. Therefore replacing incoherent beam combination with coherent is proposed.</p> <p style="margin: 0in 0in 0pt;"></p><p style="margin: 0in 0in 0pt; text-align: justify;"></p> Turbulence, Incoherent beam combining, Lens array arrangement. 145 154 http://ijop.ir/browse.php?a_code=A-10-663-1&slc_lang=en&sid=1 Sogol Tadayoni tadayyoni.sogol@gmail.com 10031947532846004491 10031947532846004491 No Department of Physics, Iran University of Science and Technology Mahdi Shayganmanesh shaygan@iust.ac.ir 10031947532846004492 10031947532846004492 Yes Department of Physics, Iran University of Science and Technology