Fiber-Laser-Pumped Er:YAG Lasers

Hybrid fiber-laser-pumped solid-state lasers exploit high-power cladding-pumped fiber lasers for direct (in-band) pumping of a crystal-based solid-state laser to reduce heating in the laser crystal, and hence allow scaling to higher power in both continuous-wave (CW) and pulsed modes of operation. In this paper, we briefly review the attractions of the hybrid laser approach for generation of output in the ~ 1.6 mum wavelength regime and consider the main design considerations for efficient operation of hybrid lasers based on Er:YAG in both CW and pulsed modes of operation. Examples of hybrid Er:YAG lasers, pumped by Er,Yb codoped fiber lasers at 1532 nm, with CW output powers up to 60 W at 1645 nm and 31 W at 1617 nm and slope efficiencies of 80% and 47% with respect to incident pump power, respectively, are described. In Q-switched mode of operation, pulse energies up to 30.5 mJ were obtained, limited by coating damage. Finally, the prospects for further increase in output power and improvement in overall performance in CW and Q-switched modes of operation will be discussed.