On the influence of the excited state migration on the population gratings amplitude recorded in the transient two wave mixing configuration in Er-doped optical fibers
E. Hernández-Hernández, Liliana O. Martínez-Martínez, Serguei I. Stepanov
In this paper we analyze the influence of a spatial migration of the excited states on suppression of the population gratings recorded in erbium-doped optical fibers (EDF). Such dynamic Bragg gratings are formed via saturation of the optical transition between the fundamental and the meta-stable states of the active ions and are observed experimentally via transient two wave mixing (TWM) of the phase-modulated counter-propagating recording waves. The reported experiments were performed in the spectral range 1492-1568nm, which covers the absorption region of the fundamental transition 4I15/2→4I13/2 of Er3+ ions. Significantly stronger grating suppression is observed at the central/long-wavelength regions of the above-mentioned spectral region. A set of similar fibers with essentially different Er3+ ions concentrations with maximum attenuation of 4, 9, 17 and 35 ± 1 dB/m at 1531 nm was investigated and a clear concentration dependence of the grating suppression was observed. The TWM measurements are supported by the original experimental data on the fluorescence depolarization. The observed spectral dependence of the grating reduction factor is explained using the model of the vacant states limited spatial migration of the excitation among the Er3+ ions.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 10, 2011•0 citations