We propose a new tandem pumping scheme in three-level rare-earth doped optical fibers where energy storage in a pump fiber laser enables much shorter (~500 ns) pump pulses than is possible with pulsed diode laser pumping. This has the effect of reducing the time during which the final amplifier has high inversion and hence reduces the ASE when compared to continuous wave (c.w.) tandem pumping. We simulate the gain and ASE dynamics in a pulse-pumped Yb-doped fiber amplifier and show that the ratio of amplified signal to ASE background can be improved by up to 2 orders of magnitude over a large range of pulse energies compared to c.w. tandem pumping. Sub-micro-second pulsed tandem pumping offers a relatively straightforward, as yet experimentally untried, way to substantially reduce undesirable ASE compared to the levels in diode-pumped fiber amplifiers.
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