Impact of Mode Filtering on the Performance of Femtosecond Pulse Amplification in a Large Mode Area Fiber

摘要

We experimentally investigated the impact of the mode filtering technique on the performances of pulse amplification in a fiber with a large core diameter. The technique was applied to a femtosecond pulse amplifier, and was based on a large area double-clad Yb-doped fiber. The mode filtering enabled selective excitation of the lowest transverse mode with minimal contamination of higher order modes. The output pulses with 110 fs duration, 30 nJ pulse energy ( 3 W average power), and clean spatial/temporal profiles were successfully generated. Benefits of this technique are also discussed.