The single beam s coupling efficiency is the key to the combined output power in incoherent fiber laser beam combination system,which is affected by focal length of lens,grating period and light spot radius.

Based on the method of ablation,a half_width definition,which is often used in engineering, is used to calculate the spot radius with spatial domain intensity comparison—a new method developed.

Through the analysis of system coupling efficiency, the spot radius should be less than 100μm,lens focus should be less than 20cm.

Based on the scanning principles,the relationship between scanning step and the characters of Gauss laser spot were expounded,The energy distribution of scanning field was analyzed,and the non-uniformity mainly depends on the stability of laser power,is about 3.