Abstract

We use numerical simulations to investigate the effects of photodarkening (PD) on pulse compression and coherent combination following chirped-pulse amplification in Yb-doped fiber amplifiers. Even though we increase the pump power to keep the pulse energy constant, PD degrades the pulses due to phase distortions resulting from heating acting already within a pulse as well as to increased self-phase modulation if the fiber length is optimized for the PD-free fiber at beginning of life. By contrast, in a fiber shorter than this, the drop in peak power is a relatively modest 35% even at a PD propagation loss as large as 5 dB, thus providing effective mitigation against PD-induced phase distortions. The improvements extend to the combination efficiency of beam-combined systems.

© 2018 IEEE

Combined effect of Yb inversion and pump photons on photodarkening in Yb laser fibers: experiments and model considerations

Sylvia Jetschke, Martin Leich, Sonja Unger, and Ulrich Röpke
J. Opt. Soc. Am. B 36(9) 2438-2444 (2019)

530 W, 1.3 mJ, four-channel coherently combined femtosecond fiber chirped-pulse amplification system

Arno Klenke, Sven Breitkopf, Marco Kienel, Thomas Gottschall, Tino Eidam, Steffen Hädrich, Jan Rothhardt, Jens Limpert, and Andreas Tünnermann
Opt. Lett. 38(13) 2283-2285 (2013)

Deep UV-induced near-infrared photodarkening of Er/Yb-doped and undoped phosphate fibers

Lingyun Xiong, Peter Hofmann, Axel Schülzgen, Nasser Peyghambarian, and Jacques Albert
Opt. Lett. 38(20) 4193-4196 (2013)

Photodarkening effect suppression in Yb-doped fiber through the nanoporous glass phase-separation fabrication method

Nan Zhao, Kangjie Peng, Jiaming Li, Yingbo Chu, Guiyao Zhou, and Jinyan Li
Opt. Mater. Express 9(3) 1085-1094 (2019)

Effective suppression of the photodarkening effect in high-power Yb-doped fiber amplifiers by H₂ loading

Ruiting Cao, Gui Chen, Yisha Chen, Zhilun Zhang, Xianfeng Lin, Bin Dai, Luyun Yang, and Jinyan Li
Photon. Res. 8(3) 288-295 (2020)