Pulse shaping in fiber lasers for high energy micromachining applications

We demonstrate a fiber laser design capable of generating shaped pulses with up to 1mJ pulse energy while keeping near diffraction limited beam quality. By controlling both the temporal and spectral characteristics of the seeder in a MOPA configuration we were able to achieve long pulses in the 100’s nanosecond range without the limiting effect of gain depletion and without reaching the detrimental SBS threshold. With this configuration we demonstrated 1mJ rectangular pulses which prove highly efficient for micromachining applications over equally energetic higher peak power gain saturated pulses.