Yb-Doped Large Mode Area Fibers Produced by Powder Sintering for High Peak Power Narrow-Linewidth Laser Source

In the last decades, Yb-doped fiber lasers proved their capabilities to deliver high average power in pulsed regime with excellent efficiencies and high beam quality [1]. To mitigate the non-linear effects that limit this technology at high peak power, Large Mode Area (LMA) fibers were developed with numerous designs and technologies. LMA fibers based on standard step-index technology [2] are relatively simple to manufacture, but they are typically limited below <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$30\mu \mathrm{m}$</tex> in Mode Field Diameter (MFD) for wavelengths around <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\mu \mathrm{m}$</tex> by index control limitations in the vapor deposition technique. On the other hand, more complex designs like Photonic Crystal Fibers (PCF) can be used to reach larger MFDs [3], but with a significant increase in complexity and cost.