32 research outputs found
3.5 kW coherently combined ultrafast fiber laser
An ultrafast laser based on the coherent beam combination of four ytterbium-doped step-index fiber amplifiers is presented. The system delivers an average power of 3.5 kW and a pulse duration of 430 fs at an 80 MHz repetition rate. The beam quality is excellent (M2<1.24·1.10), and the relative intensity noise is as low as 1% in the frequency span from 1 Hz to 1 MHz. The system is turn-key operable, as it features an automated spatial and temporal alignment of the interferometric amplification channels
Mitigation of thermally-induced performance limitations in coherently-combined multicore fiber amplifiers
Analysis of optical core-to-core coupling: challenges and opportunities in multicore fiber amplifiers
Impact of thermo-optical effects in coherently combined multicore fiber amplifiers
In this work we analyze the power scaling potential of amplifying multicore
fibers (MCFs) used in coherently-combined systems. In particular, in this study
we exemplarily consider rod-type MCFs with 2x2 up to 10x10 Ytterbium doped
cores arranged in a squared pattern. We will show that, even though increasing
the number of active cores will lead to higher output powers, particular
attention has to be paid to arising thermal effects, which potentially degrade
the performance of these systems. Additionally, we analyze the influence of the
core dimensions on the extractable and combinable output power and pulse
energy. This includes a detailed study on the thermal effects that influence
the propagating transverse modes and, in turn, the amplification efficiency,
the combining efficiency, the onset of nonlinear effect, as well as differences
in the optical path lengths between the cores. Considering all these effects
under rather extreme conditions, the study predicts that average output powers
higher than 10 kW from a single 1 m long Ytterbium-doped MCF are feasible and
femtosecond pulses with energies higher than 400 mJ can be extracted and
efficiently recombined in a filled-aperture scheme.Comment: This is a post-peer-review, pre-copyedit version of an article
published in Optics Express. The final authenticated version is available
online at: https://doi.org/10.1364/OE.41061