Wavelength-Stabilized, High-Brightness Diode Laser Pumps for High-Power Fiber Lasers

The proposed innovation is based on a combination of two new technologies developed at the Center for Laser Technology at the Fraunhofer Institute and OptiGrate Corp. and aims to integrate advanced packaging of single emitter laser diodes, spectral and angular narrowing of these diodes by volume Bragg gratings in external resonators, and spectral combining of laser beams by a stack of volume Bragg gratings, all in a robust compact laser module. The use of individual laser diodes instead of diode bars ensures high reliability and very high brightness of the combined of output power from many single emitters without the need for beam transformation. By spectrally combining several high power modules that have been locked to a very narrow linewidth our approach will result in a dramatic increase of the spectral and spatial brightness of these laser modules compared to conventional diode bars. Efficient spectral combining of beams from several modules with no penalty in power will result in a spectrum narrower than that from any conventional high power laser bar. The brightness of the proposed device will be about 1 order of magnitude higher than the current state of the art and will facilitate a 5 kW pumping source coupled to 100 um 0.22 NA fiber.