High density spectral beam combination with spatial chirp precompensation

A method for spectral combination of lasers with extremely high spectral density is introduced, enabling greater than 80% and theoretically approaching 100% spectral density utilization with no degradation in beam quality. Experiments demonstrating the utility of our method are described, cumulating in a demonstration of a compact, packaged laser with photonic-crystal-fiber-rod amplifiers at 0.5-MW peak power and 0.15-nm wavelength spacing. Our method is potentially scalable to many 100's of channels within the gain bandwidth of high average power or peak power rare earth doped fiber lasers at any wavelength in a compact footprint and uses only reflective optics and gratings. (C) 2011 Optical Society of America