2 kW random fiber laser based on hybrid Yb-Raman gain [Invited]

High-power operation is one of the most important research topics surrounding random fiber lasers (RDFLs). Here we optimized the cavity structure and proposed a new scheme based on hybrid gain to address the issue of high-power back-ward light in traditional kilowatt-level RDFLs. Consequently, a record power of 1972 W was achieved while the maximum backward leaked power only reached 0.12 W. The conversion efficiency relative to the laser diode pump power was 68.4%, and the highest spectral purity of the random lasing reached 98.1%. This work may provide a reference for high-power RDFLs, Raman fiber lasers, and long-wavelength Yb-doped fiber lasers.