The use of laser technologies in the production of optical fiber requires a careful choice of optical systems for positioning and transforming the laser beam. The purpose of this research is to determine a possibility of the redistribution of the laser beam power using diffractive optical elements. It was determined that for a radius of the focusable beam Rf = rf =2.2×10-2 m, the length of the focal spot will be increased to a value L =13.6×10-3 m, which is 1.2 times larger than Rf = rf =1.8×10-2 m. In this case, the intensity of the laser beam at the centre of the focal spot, q0 , and the maximum value, qmax , decreased by 1.1 times. An approximation of function q(x, y) by polynomials of degree n =5and m =3 was performed. It is shown that the maximal relative error of approximation does not exceed 4%, and the relative error of approximation in the centre of the focal spot does not exceed 3%. Presented equations can be used to calculate the intensity distribution in the focal plane of diffractive optical elements.