https://doi.org/10.1140/epjst/e2015-02568-6
Regular Article
Modeling of coherent beam combining from multimillijoule chirped pulse tapered fiber amplifiers
1 Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
2 Nizhny Novgorod State University, 603950 Nizhny Novgorod, Russia
3 JenLab GmbH, 07745 Jena, Germany
4 IZEST, Ecole Polytechnique, 91128 Palaiseau Cedex, France
a e-mail: alex.v.andrianov@gmail.com
Received: 19 November 2014
Revised: 31 August 2015
Published online: 26 October 2015
The amplification of high energy chirped pulses in Large Mode Area tapered fiber amplifiers and their coherent combining have been investigated numerically. We have developed a three-dimensional model of strongly chirped nanosecond pulse amplification and compression back to femtosecond duration fully taking into account transverse and longitudinal variations of refractive index profile and distribution of active ions in the fiber, wavelength dependence of emission and absorption cross sections, gain saturation and Kerr nonlinearity. Modeling of Yb-doped fiber amplifier shows that up to 3 mJ of output energy can be extracted in 1 ns pulse with single-mode beam quality. Finally, we have investigated numerically the capabilities of compression and coherent combining of up to 36 perturbed amplifying channels in which high-order modes were excited and have obtained more than 70% combining efficiency and 380 fs compressed pulse duration.
© EDP Sciences, Springer-Verlag, 2015
