Bi-Directional Pump Configuration For Increasing Thermal Modal Instabilities Threshold In High Power Fiber Amplifiers

Keywords

Beam propagation; Fiber lasers and amplifiers; Modal instability; Nonlinear effects; Power scaling; Thermal effects

Abstract

We present a time dependent computer model for modal instabilities (MI) in high power fiber amplifiers based on beam propagation method. Three regimes of temporal dynamics that are characteristic of the transfer of energy between the fundamental mode and higher order mode are captured and applied to predicting the threshold of these instabilities in absence of any frequency offset between the interfering modes. Simulation results show an increase of the instabilities threshold by a factor of approximately %30 in the case of bi-directional pump scheme with respect to the forward pump configuration. Furthermore, we estimated the MI threshold applying a coupled-mode model of thermally induced instabilities which also takes account of gain saturation to its first order approximation, and obtained reasonably good agreement with respect to our beam propagation simulation results.

Publication Date

1-1-2015

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

Volume

9344

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1117/12.2080536

Socpus ID

84931296088 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84931296088

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