Mode-scalable fiber-based chirped pulse amplification systems

A new generation of compact and robust ultrashort pulse lasers is currently emerging based on rare-earth doped fiber gain medium. This paper reviews the development of high-power fiber technology, which recently has led to millijoule energies and similar to10-W average powers from various femtosecond fiber systems. These results indicate that fiber technology has a significant potential to replace conventional solid-state lasers and promises important advantages both for practical use and for achieving high powers and energies. Chirped pulse amplification and different mode-size scaling techniques compose the foundation of this ultrashort-pulse fiber technology. Mode-size scaling can be achieved either by using multimode core fibers, which can produce a diffraction-limited beam at the fiber amplifier output, or by "mode-cleaning" of multimode core fiber output through saturated optical parametric amplification.