Multimegawatt peak-power, single-transverse-mode operation of a 100μm core diameter, Yb-doped rodlike photonic crystal fiber amplifier

The authors report on the performance of an Yb-doped, 100μm core rodlike photonic crystal fiber (PCF) used as the final amplifier in a gain-staged master-oscillator/power-amplifier source. From the PCF, they obtained 1-ns-long pulses of energy in excess of 4.3mJ, peak/average power ∼4.5MW∕42W, and spectral linewidth ∼20GHz. The PCF emitted a beam exhibiting near-Gaussian, single-transverse-mode profile of M2∼1.3.