High-power all-fiber picosecond MOPA laser based on hybrid-doped Yb fibers

Abstract

In this paper, we propose an optimized design of the picosecond MOPA fiber laser by using hybrid-doped Yb fibers. The detailed implementation is that high-doped gain fiber with relatively small fiber core is adopted in the low-power pre-amplifiers, thus the shortest fiber could be ensured and the thermal load is not so heavy. In the power amplifier stage, the normal-doped large mode area gain fiber is utilized, then the thermal effects can be minimized and the output beam quality could be ensured. The design simultaneously takes into consider the output beam quality, thermal load, nonlinear phase shift, pulse peak power of the picosecond fiber laser. With using the existed Yb-doped fibers, we demonstrate a high-power picosecond MOPA fiber laser with the proposed method. The average output power is up to 110 W, the total optical conversion efficiency is 63.2%. No stimulated Raman scattering, amplified spontaneous emission and residual pump light are observed in the output spectrum. The - 6 dB bandwidth of the output spectrum at the full output power is ~ 4 nm.