Numerical Analysis of Beam Quality Factorβ on Coherent Combination of Multiple Laser Beams

摘要

A numerical simulation model for coherent combination of multiple rectangular beams, square beams and circular beams has been developed. The beam quality factor β of wavelet and its combination was obtained by numerical calculation through fast Fourier transform (FFT) when each wavelet has Zernike aberrations with twenty-one polynomials. The influence of piston on coherent beam combination was analyzed too. It's demonstrated that the influence of piston on CBC(coherent beam combination) was small if each wavelet has many other higher order aberrations. The relationship between the averaged beam quality factor β of all wavelets and beam quality factor β of CBC based on these wavelets was also obtained by numerical calculation. A fitting formula was used to fit the discrete data. By this way, an expression of the relationship was acquired. Fitting coefficients between numerical calculation and theoretical result were compared and the affecting factor of the difference was analyzed. We concluded that fitting coefficients of numerical calculation result was smaller than theoretical result because of wavelet arrangement and filling ratio.