Spectral beam combining using superimposed reflective volume Bragg grating

Abstract

It is an effective approach to obtain high-power laser output by spectral beam combining (SBC) technologies. The power of the output beam increases with the increasing of the number of wavelength channels. However, that makes the traditional SBC system very huge for achieving high power laser output. In this paper, a simple SBC system based on the superimposed Reflective Volume Bragg Grating (RVBG) is proposed to reduce the scale of the SBC system. Two structure models of the superimposed RVBG - the superimposed RVBG with the same period and the superimposed RVBG with different period are analyzed and compared by using the rigorous coupled wave analysis, and their applications for SBC system are discussed. Numerical results show that the superimposed RVBG are easy to be fabricated and have the potential to combine multiple lasers with one volume. The superimposed RVBG with different period can achieve high diffraction efficiency simultaneously for each grating with small slant angle divergence, and is convenience to combine two beams with small spectral separation.