The invention is optical configurations for constructing laser oscillators or laser amplifiers that comprise an extremely short fiber (typically tens of cm long or below, e.g. 5 cm to 30 cm). In order to overcome the absorption limitation due to the very short length of the fiber, the present invention employs a multi pump-pass scheme for pump light confinement. This scheme is based on the small angular overlap between the lasing and pump beams. The multi pump-pass method of the invention leads to efficient fiber laser oscillators and amplifiers having pulse duration of a few ns, with high average and peak power output that is comparable to the state-of-the-art solid state lasers.