High Spectral Density Modular Spectral Beam Combiner Based on Volume Bragg Grating Technology

PD-LD, Inc. proposes to develop a novel approach to spectral beam combining utilizing the technology of monolithic volume Bragg grating (VBGT) spectral beam combiner (SBC) chips. The VBGT SBC chip is manufactured in a single monolithic piece of inorganic photorefractive glass. This technology offers high spectral resolution (£ 0.2 nm/channel) in a very compact footprint ( 200 MW/cm2) and high total efficiency (80-90%). The VBGT SBC chips that combine 10 to 20 spectral channels will be integrated into a larger system as separate module, thus offering a path to higher combined power. Our approach will maximize the spectral density of beam combination and bring it to the Rayleigh resolution criterion with high total efficiency (80% combined efficiency is expected) and nearly diffraction-limited beam quality. The approach is independent of the source lasers, offers low polarization sensitivity, and is capable of handling individual channels of extremely high power (3 1 kW). This architecture is scalable to several hundred combined channels with £ 0.2 nm/channel spectral resolution.