Advances and new applications using the acousto-optic effect in optical fibers

This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed

Magnetic Characterization Of The Mechanically Induced Thermite Reaction Between Fe2o3 And Al

We have investigated the mechanically induced self-propagating reaction between Fe2O3 and Al. In this reaction the final phases, Al2O3 and Fe, are formed by an in situ chemical reaction. The evolution of the system was characterized as a function of the milling time using X-ray diffraction, magnetometry (300 and 5 K) and Mössbauer spectroscopy (300 and 77 K). After reaction, Fe particles in a crystalline Al2O3 matrix have been formed. At larger milling times, a rather wide Fe grain size distribution of around 20 nm was obtained according to the diffraction patterns. Mössbauer spectra were constituted of both paramagnetic and ferromagnetic contributions. The former was attributed to small grains of superparamagnetic Fe (within the Mössbauer characteristic time τM ≈ 10-8s) and FeAl2O4, whereas the latter was associated to larger Fe grains. Saturation magnetization, coercivity field and remanent magnetization rapidly reached a stationary value with the milling time. A correlation between the microstructural characteristics of the sample and its magnetic properties before and after reaction is described. © 2004 Elsevier B.V. All rights reserved.3541-4 SPEC. ISS.125128Pardavi-Horvath, M., (1992) IEEE Trans. Magn., 28, p. 3186Meiklejohn, W.H., (1953) Rev. Mod. Phys., 25, p. 302Giri, A.K., (1997) Mater. Res. Bull., 32, p. 523Cuadrado-Laborde, C., (2001) Hyperfine Interactions, 134, p. 131Stewart, S.J., (2003) J. Magn. Magn. Mater., 260, p. 447Raming, T.P., (2002) J. Colloid. Interf. Sci., 249, p. 346C. Cuadrado-Laborde, et al., submittedMurad, E., (1981) Mössbauer Spectroscopy Applied to Inorganic Chemistry: Iron Oxides and Oxyhydroxides, pp. 507-582. , G.J. Long (Ed.), Plenum, Netherland

Phase recovery by using optical fiber dispersion and pulse pre-stretching

In this work, the applicability of a recently proposed phase recovery technique is extended, by using temporal pulse pre-stretching. As a proof of concept, the light pulses emitted by a two-stage laser system consisting of a sub-picosecond passively mode-locked fiber laser followed by an erbium-doped fiber amplifier were experimentally analyzed. These results were successfully compared with two indirect phase recovery techniques, both based on the Gerchberg–Saxton recursive algorithm and with the intensity autocorrelation when sub-picosecond light pulses were analyzed.Fil: Cuadrado Laborde, Christian Ariel. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); ArgentinaFil: Brotons Gisbert, M.. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo; EspañaFil: Serafino, G.. Scuola Superiore Sant’Anna. TeCIP Institute; ItaliaFil: Bogoni, A.. Inter-university National Consortium for Telecommunications. National Laboratory of Photonic Networks; ItaliaFil: Pérez Millán, P.. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo; España. FYLA LASER SL.; EspañaFil: Andres, M. V.. Universidad de Valencia. Departamento de Física Aplicada y Electromagnetismo; Españ