Person: Gómez Calderón, Óscar
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First Name
Óscar
Last Name
Gómez Calderón
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
6 results
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Now showing 1 - 6 of 6
Item Dynamic population gratings in highly doped erbium fibers(Journal of the Optical Society of America B, 2011) Melle Hernández, Sonia; Gómez Calderón, Óscar; Zhuo, Zhong C.; Antón Revilla, Miguel Ángel; Carreño Sánchez, FernandoThe efficiency of the dynamic population gratings recorded in highly doped erbium fibers has been studied. We find that the grating response increases with optical density, although the presence of erbium ion pairs in fibers with ion density of the order of 6:3 × 1025 m−3 degrades the grating efficiency. The experimental results have been reproduced including inhomogeneous upconversion processes in the nonlinear coupled-wave equations.Item Homogeneous broadening effect on temperature dependence of green upconversion luminescence in erbium doped fibers(Journal of Luminescence, 2013) Egatz-Gómez, Ana; Gómez Calderón, Óscar; Melle Hernández, Sonia; Carreño Sánchez, Fernando; Antón Revilla, Miguel Ángel; Gort, Elske M.We study the green upconversion luminescence of Er3+ ions in an aluminosilicate optical fiber upon near infrared excitation at 787 nm. The dependence of the upconversion luminescence on temperature has been determined. As temperature drops from room to cryogenic temperatures, the upconversion green emission reaches a maximum around 40 K, and then decreases. A nearly quadratic dependence of the upconversion luminescence with excitation power is found, which is consistent with a sequential stepwise two-photon absorption process. These results have been explained with a semiclassical model that considers the inhomogeneous broadening of the optical transitions due to glass imperfections, and the dependence of the homogeneous linewidth broadening on temperature.Item Propagation-induced transition from slow to fast light in highly doped erbium fibers(Physical review A, 2008) Gómez Calderón, Óscar; Melle Hernández, Sonia; Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Arrieta Yáñez, Francisco; Cabrera Granado, EduardoWe analyze the propagation regime of an amplitude-modulated 1536 nm signal when traveling along a highly doped erbium fiber pumped at 977 nm as a function of the fiber length. A propagation-induced transition from superluminal to subluminal propagation takes place along the fiber length which allows a change in regime solely based upon increasing the signal modulation frequency. This peculiar behavior is due to the interplay between pump absorption and pump-power broadening of the spectral hole induced by coherent population oscillations. The effect of ion density on this frequency-dependent regime change has been investigated.Item Phase shift of amplitude-modulated optical signals in graphene oxide water dispersions due to thermal lens focal length oscillation(Journal of the Optical Society of America B, 2014) Melle Hernández, Sonia; Gómez Calderón, Óscar; Egatz-Gómez, Ana; Cabrera Granado, Eduardo; Carreño Sánchez, Fernando; Salavagione, H. J.; Antón Revilla, Miguel ÁngelWe analyze the phase shift induced in an amplitude-modulated laser beam propagating through a water dispersion of graphene oxide sheets in a fiber-to-fiber U-bench. This phase shift arises from the thermally induced nonlinear refraction in the sample. The system exhibits strong optical limiting performance for weak continuous-wave signals. A theoretical model including beam propagation and thermal lens focal length oscillation reproduces the experimental findings.Item Modulation-frequency-controlled change from sub- to superluminal regime in highly doped erbium fibers(Optics letters, 2008) Melle Hernández, Sonia; Gómez Calderón, Óscar; Caro, César E.; Cabrera Granado, Eduardo; Antón Revilla, Miguel Ángel; Carreño Sánchez, FernandoWe report a change from sub- to superluminal propagation upon increasing the modulation frequency of an amplitude-modulated 1550 nm signal when propagating through highly doped erbium fibers pumped at 980 nm. We show that the interplay between the pump absorption and the pump-power broadening of the spectral hole induced by coherent population oscillations may drastically affect the fractional advancement or delay of the signal for the considered fibers.Item Spectral hole burning in erbium-doped fibers for slow light(Journal of the Optical Society of America B, 2012) Melle Hernández, Sonia; Gómez Calderón, Óscar; Antón Revilla, Miguel Ángel; Carreño Sánchez, Fernando; Egatz-Gómez, AnaThe homogeneous linewidth of the transition I15/24−I13/24 in highly doped erbium fibers and its dependence with temperature in the range from 10 to 50 K are experimentally characterized using spectral hole burning. The homogeneous linewidth dependence with temperature is quadratic above 20 K where homogeneous broadening is dominated by two-phonon Raman processes, and linear at lower temperatures where direct phonon processes occur. This characteristic power-law dependence was also derived from transmittance measurements. The solution of nonlinear field equations using the results obtained from our experiments predicts that Gaussian probe pulses propagate at subluminal speed through the narrow spectral holes burned in erbium-doped fibers. For gigahertz pulses in the telecommunication window, a fractional delay as high as 0.6 is predicted.