Enhanced suppression of stimulated Brillouin scattering (SBS) in high energy fiber lasers through novel chaotic phase modulation

Stimulated Brillouin scattering (SBS) poses a significant challenge in the development of high-power, single-mode continuous-wave fiber lasers. SBS occurs when the laser intensity is sufficient to generate acoustic vibrations in the fiber, leading to the reflection of light and limiting the maximum achievable power. Spectral broadening of the laser linewidth is a common SBS suppression technique. This work presents a novel approach using sine waves phase-modulated by chaotically generated noise to achieve improved SBS suppression. Experimental results demonstrate that this method achieves flatter and broader optical linewidths compared to traditional white noise modulation, even at lower power levels. This approach was successfully tested on a kilowatt-class fiber laser, and its simplicity and ability to be engineered enable unprecedented levels of spectral broadening. This work was supported by an Army SMDC Contract with the University of Alabama in Huntsville and released under USASMDC Public Affairs Office identifier Number 5062.