Spectral Combining of Five 150W Fiber Lasers by Volume Bragg Gratings in PTR Glass

摘要

The use of volume Bragg gratings (VBGs) for spectral beam combining, requires high diffraction efficiency for the diffracted beam and low diffraction efficiency for the transmitted beams simultaneously. The unique, unmatched properties of VBGs in a photo-thermo-refractive (PTR) allow spectral beam combining (SBC) achieving this condition at wavelengths with less than 0.25 nm separation. We developed a model of reflecting VBGs for high power SBC that takes into account laser spectral bandwidth, beam divergence, PTR-glass scattering losses, and grating non-uniformity.