We summarize the performance of mode-filtered, Yb-doped fiber amplifiers seeded by microchip lasers with
nanosecond-duration pulses. These systems offer the advantages of compactness, efficiency, high peak power,
diffraction-limited beam quality, and widely variable pulse energy and repetition rate. We review the fundamental limits
on pulsed fiber amplifiers imposed by nonlinear processes, with a focus on the specific regime of nanosecond pulses.
Different design options for the fiber and the seed laser are discussed, including the effects of pulse duration,
wavelength, and linewidth. We show an example of a microchip-seeded, single-stage, single-pass fiber amplifier that
produced pulses with 1.1 MW peak power, 0.76 mJ pulse energy, smooth temporal and spectral profiles, diffractionlimited
beam quality, and linear polarization.