High-power and ultrafast fiber laser and amplifier with features of high beam quality, high conversion efficiency, high pulse energy, less thermal effect, represent an attractive solution for many practically important applications, such as material processing, micromachining, solar cell manufacturing. They could overcome some problems of conventional bulk solid-state lasers and become one of research focuses in laser world due to their distinct superiorities.
Laboratory of all-solid-state light sources, Institute of Semiconductors apply a simple single-stage amplifier to realize as high as 62 W average power output at 1064 nm wavelength, 40 picoseconds pulse width and 80MHz repetition from 0.7 W seed laser based on backward pumped master-oscillator fiber power amplifier (MOPA) system. We use a SESAM passive mode-lock Nd:YVO4 oscillator as seed source and 6 m long 20 μm core double-cladding Yb-doped fiber (YDF) as gain medium. It is can stable operation in 57.6 W output for hours. None amplified spontaneous emission (ASE) and stimulated Raman scattering (SRS) phenomena were observed in 57.6 W high average power output. To our best knowledge it is the highest power output of single-stage amplifier with backward direction pump in 20 μm fine core fiber.
Fig. 1 Experimental setup
Fig. 2 Output power of the amplifier against LD pump power