Abstract

HERNANDEZ HERNANDEZ, E.; MARTINEZ MARTINEZ, L.  and  STEPANOV, S.. Dynamics of the population grating formation in erbium-doped fibers. Rev. mex. fis. [online]. 2015, vol.61, n.6, pp.458-465. ISSN 0035-001X.

Experimental results on formation dynamics of population gratings in erbium-doped fiber (EDF) investigated via two-wave mixing (TWM) are reported. It is shown that at all three utilized essentially different recording wavelengths 1492, 1526 and 1568nm the transient TWM response in EDF with low erbium concentration (≈ 640 ppm) has the characteristic rate significantly larger than that of the population of the Er³⁺ meta-stable level evaluated from the fluorescence dynamics. Additionally in EDF with high erbium concentration (≈ 5600 ppm) the TWM response is faster (even at low recording power) and the relative TWM amplitude is lower than that in EDF with low concentration. General increase of the TWM response rate is explained by contribution of a transient decrease of the fiber average absorption level, while above-mentioned differences observed in heavily doped EDF - by spatial migration of the excited states. The spectral dependence of the later effect is attributed to the difference in the absorption/emission cross-section ratio of the Er³⁺ ions at the utilized wavelengths.

Keywords : Dynamic population gratings; two-wave mixing; erbium doped fibers.

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