SBC of high-power fiber lasers uniquely links an efficient, versatile, and robust power scaling architecture to individual emitters with outstanding efficiency, diffraction-limited beam quality, and distributed thermal loading. Fiber SBC, thus provides an exceptionally promising pathway to scalable, high efficiency laser systems with high average power, superb power-to-mass ratios, and near perfect beam quality. Below, we describe the proposed technical program for the Phase II effort. The program focuses on improving the efficiency and performance of a >1 k-Watt fiber laser channel, demonstrating the destructive capabilities of such a laser, advancing the SBC module by increasing its overall efficiency and characterizing the ability of a SBC module to steer the beam without sacrificing efficiency and beam quality.