INSTITUTE OF APPLIED PHYSICS - High-power ultrashort-pulse laser systems

High-power ultrashort-pulse laser systems

Active fibers possess many inherent advantages such as a large surface-to-volume ratio, a high signal gain and an excellent beam quality. These properties result in compact, single-pass and even monolithic ultrashort-pulse laser systems, which are capable of emitting average powers up to the kilowatt level. But also in terms of the available pulse energies and peak-powers, state-of-the-art fiber lasers have become competitive to other solid-state-laser concepts. The reason for the tremendous performance increase that has been seen in recent years is the exploitation and steady improvement of three technologies: chirped-pulse amplification (CPA), large-mode-area fibers and coherent pulse combination (CPC). The first two concepts reduce the intensity in the fiber core during propagation and they, therefore, allow for average and peak-power scaling. Additionally, coherent pulse combination distributes the power to multiple fibers or multiple temporal replica.


Highly efficient dielectric diffraction grating employed in a CPA stretcher/compressor unit.

In our group we are operating different Ytterbium and Thulium based high-power fiber-CPA systems. They are steadily improved and employed for different applications. The related research includes many different fields of ultrafast optics and laser physics. Our main topics include fiber design, pulse stretching and compression techniques, active and passive pulse shaping, investigations on the dynamics of nonlinear CPA systems, pump concepts, cooling techniques and much more.

Laser amplifier_AG JL
Laser amplifier comprising 16 coherently combined Ytterbium rod-type fiber amplifiers.

As a result of these efforts, the fiber-CPA systems, which are developed and build at the IAP, possess the world's largest average powers, pulse energies and peak powers. Furthermore, many of these lasers are worldwide used for a variety of applications within the framework of our scientific and industrial cooperation.

Selected publications:

[1] M. Kienel, M. Müller, A. Klenke, J. Limpert, and A. Tünnermann, "12 mJ kW-class ultrafast fiber laser system using multidimensional coherent pulse addition,"
Opt. Lett. 41, 3343-3346 (2016). link to journal

[2] M. Müller, A. Klenke, A. Steinkopff, H. Stark, A. Tünnermann, and J. Limpert,
"3.5 kW coherently combined ultrafast fiber laser," Opt. Lett. 43, 6037 (2018).
link to journal

[3] C. Gaida, M. Gebhardt, T. Heuermann, F. Stutzki, C. Jauregui, and J. Limpert, "Ultrafast thulium fiber laser system emitting more than 1  kW of average power," Opt. Lett. 43, 5853-5856 (2018). link to journal