Photodarkening-induced phase distortions and their effects In single-channel and coherently combined Yb-doped fiber chirped pulse amplification systems

Feng, Yujun, Zhang, Betty Meng and Nilsson, Johan (2018) Photodarkening-induced phase distortions and their effects In single-channel and coherently combined Yb-doped fiber chirped pulse amplification systems. Journal of Lightwave Technology, 36 (23), 5521-5527. (doi:10.1109/JLT.2018.2874086).

Record type: Article

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.

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IEEE Photo Darkening Heating Induced Phase Distortion - Author's Original

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Photodarkening-Induced Phase Distortions And Their Effects In Single-Channel And Coherently Combined Yb-Doped Fiber Chirped Pulse Amplification Syste - Accepted Manuscript

Available under License University of Southampton Accepted Manuscript Licence.

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