Numerical analysis of spectral beam combining by volume Bragg grating

The physical models of spectral beam combining for two beams and three beams by one and two reflective volume Bragg gratings(VBG) are founded in this article. The physical models consider the absorbability of VBG and suppose that the incident beam has a Gaussian shape. Two and three spectral beams combinings are numerically analyzed. When the spectral width is 0.1 nm, the spectral beam combining efficiencies are 98.76% and 97.69%, and when the spectral width is 0.3 nm, the spectral beam combining efficiencies are 97.34% and 95.78%, respectively. The increscent spectral width decreases the spectral beam combining efficiency. The results show that the high spectral beam combining efficiency for more beams can be obtained by this method, which provides a doable way for high power laser.