SBS suppression in a narrow-linewidth fiber amplifier with cylindrical vector mode transformation and nonlinear spectral compression

In this paper, we investigated the SBS suppression potential in a fiber amplifier with both cylindrical vector beam output and nonlinear spectral compression method applied. By applying different kinds of modes output and different spectral management schemes, the SBS threshold of a same fiber amplifier was measured to be 67 W, 95 W and 104 W. These schemes correspond to LP₀₁ mode output with spectrum maintained, TM₀₁ mode output with spectrum maintained and TM01 mode output with spectrum narrowed, respectively. Experimental results indicated that the SBS threshold of our fiber amplifier with cylindrical vector beam output and spectrum compressed can be enhanced by 1.56 times, comparing to the traditional Gaussian beam one. The combination of the two techniques can pave the way for mitigating the SBS effect in high-power narrow-linewidth fiber amplifiers.