Temporally and spatially shaped fully-fiberized ytterbium-doped pulsed MOPA

We report a fully-fiberized, pulsed ytterbium-doped master oscillator power amplifier (MOPA) for materials processing applications providing both a temporal pulse and spatial beam shaping capability operating at a maximum average output power of 100 W. Adaptive temporal pulse shaping using an in-line electro-optic modulator was incorporated to reduce the impact of dynamic gain saturation and optical Kerr/Raman nonlinearities. The MOPA is capable of generating 2.5 mJ flat-topped optical pulses with 20 kW peak power as well as other user-defined, shaped pulses. Spatial beam shaping is obtained using a pair of axicon (conical) lenses at the end of the beam delivery optic allowing ring shaped output beams to be generated from the otherwise collimated Gaussian output