We have developed and demonstrated both Ytterbium-doped and Erbium-doped, diode-pumped and seeded, fiber amplifiers at 1064 and 1570 nm, respectively. By pulse pumping a one-stage Erbium amplifier, we have shown greater than 20 W peak output power and high wall-plug efficiency.  Our pulse-pumping approach improves energy efficiency up to 80% (at 1 kHz PRF) over the identical CW pumping scheme while suppressing amplified spontaneous emission (ASE).  We report on the development of these rare-earth doped fiber amplifiers and the application of multi-stage fiber amplifiers to create a multi-spectral laser transmitter ideally suited for space and planetary lidar investigations.