3.5 kW narrow-linewidth FBG-based MOPA fiber lasers with high signal to noise ratio

Abstract

One-stage master oscillator power amplifier (MOPA) is an efficient way to acquire high-power narrow-linewidth fiber lasers (NLFLs), which have wide usage in beam combination and detection. In this paper, we set up a narrow-linewidth one-stage MOPA fiber laser system which utilize a compact fiber oscillator as the seed laser. By optimizing the temporal characteristics of seed laser with a backward pumping structure of amplification stage, we finally acquire a 3.5 kW near single mode laser output with 3 dB and 20 dB linewidth of 0.26 nm and 1.1 nm, respectively. The slope efficiency reaches to 83.4%. At the maximum power, the signal to noise ratio ratio is ~60 dB on the spectrum and the M2 factor is measured about 1.3.

1.2 kW, 20 kHz Nanosecond Nd:YAG Slab Laser System

“…Yongxi Gao demonstrated a 417 W, 175 kHz, 2.38 mJ innoslab chirped pulse amplification laser [14]. Additionally, fiber lasers have achieved high levels of average power output [15][16][17], but their single-pulse energy is limited by the issue of fiber core damage, resulting in relatively low single-pulse energy, typically in the range of a few millijoules. Furthermore, due to the small diameter of the fiber core, nonlinear effects such as stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and self-phase modulation (SPM) easily occur during the amplification process.…”