Fiber lasers and amplifiers. An ultrafast performance evolution

The first rare-earth-doped fiber lasers were operated in the early sixties and produced a few milliwatts at a wavelength around 1 µm. For the next several decades, fiber lasers were little more than a low-power laboratory curiosity. Recently, however, fiber lasers are entering the realm of kilowatt powers in continuous as well as in pulse operation with diffraction-limited beam quality. In this article we review this power evolution.