Enhancement of stimulated Brillouin scattering of higher-order acoustic modes in single-mode optical fiber

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-30-20-2685. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Solving the elastic wave equation exactly for a GeO2-doped silica fiber with a steplike distribution of the longitudinal and shear velocities and density, we have obtained the dispersion, attenuation, and fields of the leaky acoustic modes supported by the fiber. We have developed a model for stimulated Brillouin scattering of these modes in a pump-probe configuration and provided their Brillouin gains and frequencies for an extended range of core sizes and GeO2 doping. Parameter ranges close to cutoff of the acoustic modes and pump depletion enhance the ratio of higher-order peaks to the main peak in the Brillouin spectrum and are suitable for simultaneous strain-temperature sensing.Shahraam Afshar V., V. P. Kalosha, Xiaoyi Bao, Liang Che

Temporal structure of stimulated-Brillouin-scattering reflectivity considering transversal-mode development

The time-resolved reflectivity of optical phase conjugation by stimulated Brillouin scattering ~SBS! is investigated both theoretically and experimentally. A three-dimensional and transient model of SBS is developed to compare the experimental and theoretical results. Noise initiation of the SBS process is included in the model to simulate the shot-to-shot variation in the reflectivity and the Stokes temporal profile.Shahraam Afshaarvahid, Axel Heuer, Ralf Menzel, and Jesper Munc

Effect of the finite extinction ratio of an electro-optic modulator on the performance of distributed probe-pump Brillouin sensorsystems

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-28-16-1418. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Shahraam Afshar V., Graham A. Ferrier, Xiaoyi Bao, Liang Che

Nature of intensity and phase modulations in stimulated Brillouin scattering

The nature of stimulated Brillouin scattering (SBS) temporal modulations for a focused beam in a finite-length cell with homogeneous medium is examined numerically. The finite phonon lifetime produces deterministic oscillations at the threshold while the inclusion of the random noise as an initiation source of SBS leads to stochastic fluctuations in Stokes intensity and phase. A unified study of both modulations under different parameters is presented. The results indicate a large useful parameter space for excellent Stokes beam quality.Shahraam Afshaarvahid, Vladimyros Devrelis, and Jesper Munc

Transient phase conjugation using Stimulated Brillouin Scattering / by Shahraam Afshaarvahid.

Copies of author's previously published articles inserted.Bibliography: p. 169-176.vii, 176 p. : ill. ; 30 cm.Develops a one and three dimensional transient model of Stimulated Brillouin Scattering to investigate the transient regime of Stimulated Brillouin Scattering and recognize different transient phenomena that affect its performance.Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2001

A transient, three-dimensional model of stimulated Brillouin scattering

© World Scientific Publishing CompanyAn efficient numerical 3-D model of transient stimulated Brillouin scattering (SBS) is reported. The model is used to examine the effects of transient phenomena on the efficiency of phase conjugation by SBS and the mode structure of the Stokes and pump pulse inside the SBS cell. The effect of parameters such as phonon lifetime, input pulse shape and input energy on the transient fidelity of SBS is investigated. A new transient phenomenon which causes SBS fidelity degradation at high focal intensity (short Rayleigh range) is examined