134 W, 1.34 mJ, 240 fs ultrashort pulses from a rod-type photonic crystal fiber amplifier

We have demonstrated a high peak power and high beam quality infrared femtosecond laser based on an all-fiber chirped pulse amplification (CPA) system. The Yb-doped fiber preamplifier uses a short, large-mode-area silica photonic crystal fiber (PCF) pumped by a fiber combiner, which reduces the limitations caused by the accumulation of a nonlinear phase. The main power amplifier is based on a rod-type Yb-doped PCF. It delivers an average power of 148 W at a repetition rate of 100 kHz. The laser pulses are compressed using a compact bulk transmission grating compressor. By minimizing the accumulation of nonlinear effects and optimizing dispersion compensation in the CPA system, a short pulse duration of 240 fs, an average power of 134 W, and a pulse energy of 1.34 mJ are achieved. The laser pulses exhibit excellent beam quality and high-power stability. The M 2 value is less than 1.1, and the RMS of the power stability is below 0.7% over 8 hours. The outstanding performance of this system has broad applications in industrial and scientific research fields.