Jens Limpert

High Repetition Rate Tunable Femtosecond Pulses from Fiber Laser Pumped Parametric Amplifier

High-energy femtosecond pulses at 1 MHz from a fiber-laser-pumped optical parametric amplifier are demonstrated. A broadband seed from a photonic crystal fiber enables tunability simply by adjusting the temporal delay between pump and signal.

1 kW Narrow-Linewidth Fiber Amplifier for Spectral Beam Combining

We report on a narrow linewidth fiber amplifier system emitting a total output power of 1 kW. Limiting nonlinear effects like stimulated Raman and Brillouin scattering as well as self-phase modulation are discussed in detail.

Hybrid 400W Fiber-Innoslab fs-Amplifier

Combining fiber- and Innoslab technology enables up to 420W average output power at almost diffraction limited beam quality. Pulses compressible to τ=720 fs at 1MHz and 100kHz repetition rate have been achieved so far.

Gain Limitations and Consequences for Short Length Fiber Amplifiers

We numerically and experimentally analyze gain limitations due to pump light bleaching in large core short length fiber amplifiers and discuss consequences such as the efficiency and accumulated nonlinear phase.

Double-Pass versus Single-Pass Fiber Amplification: A Numerical and Experimental Comparison

A modified Frantz-Nodvick equation is applied to investigate pulsed amplification in ytterbium-doped fibers. Conditions under which single or double pass configuration is preferable are pointed out. The results are compared with experiments.

Concept for CEP-stable few-cycle pulses at 100 W average power

We present the system design and first experimental results of the ELI-ALPS HR1 laser system. At the output CEP-stable few-cycle pulses with 1 mJ energy, >0.1 TW peak power and 100 W of average power will be generated.

Wavelength Dependence of Maximal Diffraction-Limited Output Power of Fiber Lasers

We experimentally studied the influence of different operation wavelengths on the heat-load in a fiber-laser. Photodarkening and quantum-defect heating results in an unexpected wavelength dependence of mode-instabilities. We provide guidelines to maximize the diffraction-limited output-power.

Modeling the suppression of stimulated Raman scattering in active and passive fibers by lumped spectral filtering elements

Stimulated Raman scattering in optical fibers can be suppressed by different techniques, which include the use of special fiber designs (that work as distributed spectral filters) [1] or the use of lumped filtering elements. Fiber designs like the w-type profile are limited in maximum fiber core size and provide Raman attenuations of a few dB/m. These characteristics imply that these designs are not suitable for high power fiber amplifiers with short fiber lengths. In these applications lumped filters could provide a better and more flexible solution. Thus, in this work lumped filters will be evaluated as Raman suppression elements in passive fibers as well as in active Yb-doped fibers for amplifier and laser applications. Both the influence of the number of equidistant discrete filters in various setups and the impact of their insertion losses will be theoretically studied.

105 kHz, 85 ps, 3 MW Peak Power Microchip Laser Fiber Amplifier System

We report on a fiber amplified passively Q-switched microchip-laser delivering 85ps pulses with an energy of up to 0.26mJ, corresponding to a peak-power of 3MW. The repetition rate is 105kHz, resulting in 27W average power..

High Energy and High Average Power Q-Switched Photonic Crystal Fiber Laser

We report on the generation of sub-10-ns pulses with 2.5 mJ energy at low repetition rates and up to 100-W average power at 100-kHz from a Q-switched fiber laser with a 60 µm single-transverse-mode core.