Study on the Influence of Phase Noise on Coherent Beam Combined Bessel–Gaussian Beam

Coherent beam combining (CBC) technology is one of the effective methods to obtain the high power laser beam, but the quality of the combined beam is significantly affected by the random phase noise among the sub-beams. In this work, a method for generating a combined Bessel–Gaussian(CBG) beam based on CBC technology is proposed. The correlation coefficient is adopted to evaluate the influence of phase noise on CBG beam including the Gaussian phase noise (GPN) and measured fiber laser phase noise (FLPN). The research results of GPN show that the spiral phase of the n-order CBG beam is unaffected by noise when the amplitude of phase noise is less than λ/5. The phase noise of fiber laser is measured, and its amplitude is around λ/10. Therefore, the spiral phase of the CBG beam is unaffected by the measured FLPN. Moreover, the resisted ability of the CBG beam against phase noise is improved efficiently through increasing the number of sub-beams.