Fiber-coupled laser pumps with low size, weight and power consumption (SWaP) have become more and more compelling for applications in both industrial and defense applications. This study presents an innovative approach employing the spectral beam combining technique and double-junction laser diode chips to create efficient, high-power, high-brightness fiber-coupled packages. We successfully demonstrated a wavelength-stabilized pump module capable of delivering over 560 W of ex-fiber power with an electro-optical conversion efficiency of 55% from a 135 μm diameter, 0.22 numerical aperture fiber. The specific mass and volume metrics achieved are 0.34 $\mathrm{kg}/\mathrm{kW}$ and 0.23 ${\mathrm{cm}}^3/\mathrm{W}$, respectively. The module exhibits a stabilized spectrum with a 3.6 nm consistent interval of two spectral peaks and a 4.2 nm full width at half maximum across a wide range of operating currents.

High-brightness fiber laser sources usually utilize active rare-earth-doped fibers cladding-pumped by multimode laser diodes (LDs), but they operate in limited wavelength ranges. Singlemode-passive-fiber based Raman lasers are able to operate at almost any wavelength being pumped by high-power fiber lasers. One of the interesting possibilities is to directly pump graded-index (GRIN) multimode passive fibers by available high-power multimode LDs at 915–940 nm, thus achieving high-power Raman lasing in the wavelength range of 950–1000 nm, which is problematic for rare-earth-doped fiber lasers. Here we review the latest results on the development of all-fiber high-brightness LD-pumped sources based on GRIN fiber with in-fiber Bragg gratings (FBGs). The mode-selection properties of FBGs inscribed by fs pulses supported by the Raman clean-up effect result in efficient conversion of multimode pump into a high-quality output beam at 9xx nm. GRIN fibers with core diameters 62.5, 85 and $100~\unicode[STIX]{x03BC}\text{m}$ are compared. Further scaling capabilities and potential applications of such sources are discussed.