Compact 50W ultrashort pulse fiber laser for precision and high-speed material processing

We have previously demonstrated ultrashort pulse amplification in fiber systems beyond the B-integral limit. Here we report on recent experiments to increase the average power of such systems, and their application to high-speed material processing. A compact fiber chirped pulse amplification system, producing sub-picosecond 50 mu J pulses at a repetition rate of 1 MHz, is obtained by implementing a fiber stretcher and a 1780 l/min dielectric diffraction grating compressor. Despite a substantial residual dispersion mismatch between stretcher and compressor, the cubicon fiber amplifier allows for the generation of sub-picosecond pulses with sufficient quality for high-speed micromachining applications. Moreover, the dielectric grating compressor allows power independent near-diffraction limited beam quality as required for precision micro-machining. We utilize this laser to mill aluminum, alumina, and glass targets with material removal rates > 0.2 mm(3)/s in all three materials.