High-Energy Single-Frequency Core-Pumped Er-Doped Fiber Amplifiers

In this article, we studied high-energy single frequency transform-limited Er-doped amplifiers core pumped by a specially developed Yb-doped fiber laser at 980 nm and a Raman laser at 1480 nm. It was demonstrated that pumping at 1480 nm allows achieving slightly higher maximum pulse energy for long pulses in the absence of nonlinear effects. At the same time, amplifiers with a pump at 980 nm have a higher threshold of stimulated Brillouin scattering (SBS), and higher peak power of shorter pulses can be achieved in such a scheme. Lasers with more than 730 μJ pulse energy and with higher than 3.5 kW peak power were demonstrated.