Fiber Lasers

Fiber lasers are applicable in many different areas ranging from bio analysis and spectroscopy over various sensing technologies to material processing.

Our research activities fall within the rapidly growing field of high-power fiber lasers. Fiber lasers are expected to replace solid-state lasers in a wide range of applications due to their superior properties with respect to stability, production, maintenance costs, and ease of use. In our group, we combine theoretical and experimental work to overcome a variety of the current challenges to fiber laser technology.


On the theoretical side the fundamental problem is to describe the nonlinear light propagation arising from the strong light-matter interaction at high powers. One present-day challenge is to model short-pulse propagation under Kerr and Raman nonlinearities in complex fiber structures, e.g. photonic-bandgap fibers, or in multimode fibers, where nonlinear interactions between different modes is a big theoretical challenge. A more recent set of problems is connected with the nonlocal thermo-optic nonlinearities currently limiting the power scaling of high-power fiber amplifiers. Our group has pioneered the development of efficient propagation models for this problem, and is currently focusing on extending the theory to multipass amplifiers/lasers and more advanced fiber geometries.


On the experimental side we benefit from our close and long-standing collaboration with industry, e.g. NKT Photonics A/S and OFS Fitel, giving us access to state-of-the art fibers and well-equipped industrial laboratories. A large number of our experimental projects are done in collaboration with these companies. Current topics of interest includes high-power Yb-doped amplifiers (hundreds of watts..), the use of four-wave mixing effects to extend the spectral range of Yb-doped fiber lasers, and high-power pulse delivery in advanced photonic bandgap fibers or by controlled use of higher-order modes.


In addition to our industrial partners, we collaborate with a number of foreign groups on the subject of ultrafast fiber lasers and their use for bio-imaging applications. These include the group of Dr. Dmitry Turchinovich in Mainz, professor Ömer Ilday, Bilkent University, Turkey, and Professor Stephen Boppart, University of Illinois, Urbana-Champaign.