kW-class nanosecond pulsed polarized MOPA fiber laser at 2050 nm and 2090 nm

We report on the development of a pulsed MOPA laser as a pump source for nonlinear fibers, for supercontinuum generation, or optical parametric generation in the mid-IR. The master oscillator is a directly modulated semiconductor laser, while the power amplifier is a two-stage polarization-maintaining fiber amplifier. Such a laser setup allows a flexible output pulse. We investigate the amplification of pulses from 5 to 50 ns long with pulse frequencies from 10 kHz to 1 MHz at a signal wavelength of 2050 or 2090 nm with the goal of kW peak power level for a rectangular output pulse shape.