Power scaling of the in-band diode-pumped Er-nanoparticle-doped fiber laser (Conference Presentation)

Successful power scaling of the Er-doped fiber laser heavily depends on Er dopant concentration. In order to scale the power up to a kW class, core absorption should be well over the limits defined by current commercial doping techniques. Recently developed nanoparticle (NP) doping technique of fabrication of erbium-doped fibers allows the desired dopant concentration increases while mitigating both Er upconversion and clustering effects. Here we present the latest resonantly-pumped Er fiber laser power scaling results enabled by further development of the NP doping technique of Er-doped fiber fabrication. Using resonantly cladding-pumped (at 1530 nm) large mode area 20/125 µm fiber with the Er-NP-doped core we achieved pump-limited CW power of over 30 W at ~1605 nm with the slope efficiency versus absorbed pump power of ~63%. These are, to the best of our knowledge, the highest power and efficiency demonstrated so far for from the Er-NP-doped fiber. Further considerations on fiber design optimization are presented as well.