1.1-kW Ytterbium Monolithic Fiber Laser With Assembled End-Pump Scheme to Couple High Brightness Single Emitters

We demonstrate a continuous-wave all-fiber laser with master oscillator and two-stage power amplifier configuration. Diode pumping with single-emitter technology is used with the advantage of low cost and outstanding heat management. An assembled end-pumped scheme is employed to couple high brightness pump power into a gain fiber. The laser system generates 1.1-kW output power at 1085 nm, with the total optical-optical efficiency of about 66.5%, corresponding to 1655 W of applied pump power. The variable absorption of gain fiber is analyzed considering the launching spectra characteristics of single emitters, which is significant for the construction of the pump system.