Confined Doping LMA Fibers for High Power Single Frequency Lasers

Fiber laser systems with high average power, narrow linewidth, and nearly diffraction limited beam quality are desirable for applications in areas such as gravitation wave detection or directed energy. In particular, these systems have special fiber design requirements and finding the right balance between large mode areas to mitigate unwanted nonlinear effects such as Stimulated Brillouin Scattering (SBS) while maintaining fundamental mode operation is a challenging task. A promising approach to achieve this goal relies on confining the rare earth dopant to the central region of the central LMA core and therefore providing preferential gain to the fundamental mode while simultaneously minimizing the spatial overlap of the optical wave with the resulting acoustical wave during operation. In this work, we investigate the SBS properties of LMA fibers with confined Ytterbium doping and numerically compare the amplifier performance with homogeneously doped large mode area gain fibers and the corresponding high-power single frequency SBS thresholds.

Automated summary

The SBS properties of LMA fibers with confined Ytterbium doping are investigated, and the amplifier performance is numerically compared with homogeneously doped large mode area gain fibers and the corresponding high-power single frequency SBS thresholds.