Accurate analysis of coherent beam combining of fiber laser

In order to study the properties of fiber laser and coherent combining beam accurately,the propagation properties and beam quality of LP01 mode and the field of coherent combining beam were analyzed in terms of the method that the mode of LP01 was decomposed into orthonormal Laguerre-Gaussian modes.Then the beam quality and the propagation field were compared with that of Gaussian beam which is usually used to describe fiber laser.The results show the far field distribution of LP01 mode and that of Gaussian beam are much different after transmission though their initial field distribution is the same,and the difference between the field of coherent combination of LP01 mode and that of Gaussian beam is obvious.For accurate analysis of the properties of coherent beam combination,the expression of the Laguerre-Gaussian modes of a fiber laser should be used.