The major challenge in the development of monolithic kW class CW fiber lasers is the efficient conversion of pump
photons into a high brightness laser beam under the constraints of heat management, long term stability and
nonlinearities. This article reviews the interaction of some fiber related aspects as e.g. fiber core composition,
photodarkening and modality, as well as their influence on system complexity and power scalability. Recent work on
active fibers, pump couplers, mode field adaptors and other fiber-optic components will be presented.
We report on the generation of pulse average power in excess of 1W (at pulse repetition rate ~100 kHz) in the 3.8-4micron wavelength range, obtained from a periodically-poled lithium niobate optical parametric oscillator pumped by a nanosecond-pulse, high-power 1545nm-wavelength pulsed fiber source.
In recent years fiber pulsed fiber lasers have began to challenge diode pumped solid state lasers in
performance. In particular double-clad fiber lasers and amplifiers with mJ energies and near diffraction
limited beam quality are gaining respect for applications such as materials processing, laser radar and
remote sensing. Frequency conversion of single-polarization fiber lasers further increases the application
space to such as underwater communications, underwater imaging, semiconductor processing and gas
Yb fiber lasers have to date produced several mJ pulse energy and several MW peak power but, largely
due to materials issues Er based fiber laser systems underperforms in comparison. Relevant technologies