Influence of a backward reflection on low-threshold mode instability in Yb 3+ -doped few-mode fiber amplifiers
An influence of backward reflection on spatio-temporal instability of the fundamental mode in Yb -doped few-mode polarization maintaining fiber amplifiers with a core diameter of 10 μm was studied experimentally and theoretically. The mode instability threshold was registered to decrease dramaticall...
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Veröffentlicht in: | Optics express 2016-06, Vol.24 (13), p.14871 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | An influence of backward reflection on spatio-temporal instability of the fundamental mode in Yb
-doped few-mode polarization maintaining fiber amplifiers with a core diameter of 10 μm was studied experimentally and theoretically. The mode instability threshold was registered to decrease dramatically in the presence of a backward reflection of the signal from the output fiber end; an increase of the signal bandwidth or input power resulted in the increase of the threshold. Numerical simulation revealed a self-consistent growth of the higher-order mode LP
and a traveling index grating accompanying the population grating induced by the mode interference field (due to different polarizability of the excited and unexcited Yb
ions). The presence of the backward-propagating wave resulted in four-wave mixing on the common index grating induced by the interference field of pairs of the fundamental LP
and LP
modes. |
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ISSN: | 1094-4087 1094-4087 |
DOI: | 10.1364/OE.24.014871 |