Showing papers on "Brillouin scattering published in 2004"
TL;DR: In this paper, the authors presented an accurate numerical simulation of the Brillouin gain spectrum (BGS) in single-mode fibers and revealed a tendency of the peak BGS gain coefficient that determines the stimulated BrillouIN scattering threshold.
Abstract: For many fiber applications, the Brillouin gain spectrum (BGS) contains important information including the Brillouin frequency shift, the Brillouin spontaneous linewidth, and the Brillouin gain coefficient. This paper is the first, to the best of our knowledge, to present an accurate numerical simulation of the BGS in single-mode fibers. The simulated and measured BGS were in good agreement. Through repeated numerical simulations, we revealed a tendency of the peak Brillouin gain coefficient that determines the stimulated Brillouin scattering threshold.
235 citations
Patent•
25 Jun 2004
TL;DR: In this paper, a distributed optical fiber sensor utilizing the Brillouin scattering phenomenon was proposed, which is capable of measuring strain and temperature with high accuracy and high spatial resolution without requiring any manual adjustment.
Abstract: A distributed optical fiber sensor capable of measuring strain and/or temperature with high accuracy and high spatial resolution without requiring any manual adjustment. The distributed optical fiber sensor utilizing the Brillouin scattering phenomenon comprises a stepwise optical pulse light source generating an optical pulse having a stepwise distribution of light intensity increasing toward the center, a CW light source generating a continuous light, a sensing optical fiber which receives an optical pulse as a probe light and the continuous light as a pumping light and in which a Brillouin scattering phenomenon occurs between the probe light and the pump light, and a Brillouin time domain detector for determining the Brillouin loss or the gain spectrum from the light emerging from the sensing optical fiber and attributed to the Brillouin scattering phenomenon, and determining the distribution of strain caused in the sensing optical fiber in the longitudinal direction thereof and/or the distribution of temperature from the Brillouin loss or gain spectrum.
171 citations
Book•
15 Jun 2004
TL;DR: In this paper, the Nonlinear Schroedinger Equation (NSE) was used to describe the nonlinear effects of linear and nonlinear optical effects in optical signal processing.
Abstract: Introduction.- Part I. Fundamentals of Linear and Nonlinear Optics.- Overview of Linear Optical Effects.- Optical Telecommunications.- Nonlinear Effects.- Part II. The Nonlinear Schroedinger Equation.- Self- and Cross-Phase Modultion.- Four-Wave-Mixing FWM.-Intrachannel Nonlinear Effects.- Solitons.- Raman Scattering.- Brillouin Scattering.- Part III. Applications of Nonlinear Effects in Telecommunications.- Optical Signal Processing.- Nonlinear Lasers and Amplifiers.- Nonlinear Optical Phase Conjugation.- Apendices.- Solutions to the Exercises.- References.
160 citations
TL;DR: The feasibility of the highly precise simultaneous measurement of temperature and strain by use of the PCF in a distributed Brillouin sensing system with a spatial resolution of 15 cm is demonstrated.
Abstract: The dependence of the Brillouin frequency shift on strain in a photonic crystal fiber (PCF) was measured at a wavelength of 1320 nm for the first time to the authors’ knowledge. Together with measurements of the dependence of the Brillouin frequency shift on temperature in the PCF, we demonstrate the feasibility of the highly precise simultaneous measurement of temperature and strain by use of the PCF in a distributed Brillouin sensing system with a spatial resolution of 15 cm.
138 citations
TL;DR: In this article, an experimental and theoretical study of the coherent Rayleigh-Brillouin scattering in gases in the kinetic regime was presented, where a probe laser beam was then coherently scattered from the perturbation waves.
Abstract: We present an experimental and theoretical study of the coherent Rayleigh-Brillouin scattering in gases in the kinetic regime. Gas density perturbation waves were generated by two crossing pump laser beams through optical dipole forces. A probe laser beam was then coherently scattered from the perturbation waves. The line shape of the scattered light was modeled using kinetic theory. The model takes into account the internal energy modes of the gas particles and is applicable to both molecular and atomic gases. We discuss the implication of coherent Rayleigh-Brillouin scattering on kinetic theory and photon matter interaction.
110 citations
TL;DR: This novel technique is shown to provide high-resolution characterization of SBS even under saturation operation in a simple and stable setup in which the spectrum is translated from the optical to the electrical domain, sweeping the frequency of an electrical signal generator.
Abstract: We introduce an enhanced method for the characterization of stimulated Brillouin scattering (SBS) spectra in single-mode fiber that is based on optical single-sideband modulation. This novel technique is shown to provide high-resolution characterization of SBS even under saturation operation in a simple and stable setup in which the spectrum is translated from the optical to the electrical domain, sweeping the frequency of an electrical signal generator. Experimental results are used to demonstrate the performance of the system in measuring the detailed structure of acoustic modes in three types of single-mode fiber.
99 citations
TL;DR: An Er:Yb codoped fiber amplifier chain for the generation of pulses for coherent lidar applications at a wavelength near 1.5 microm is reported.
Abstract: An Er:Yb codoped fiber amplifier chain for the generation of pulses for coherent lidar applications at a wavelength near 1.5 micron is reported. The final 1.8-m-long power amplification stage had a 50 micron core diameter and yielded a 23-dB energy gain, resulting in 0.29-mJ, 100-ns pulses at a repetition rate of 4 kHz with no Brillouin scattering and an M2 of 2.1.
98 citations
TL;DR: An analysis of the effects of ion trapping on ion acoustic waves excited by the stimulated Brillouin scattering of crossing intense laser beams is presented in this paper, along with reasonably successful comparisons of the theory to results from particle simulations and laboratory experiments.
Abstract: An analysis of the effects of ion trapping on ion acoustic waves excited by the stimulated Brillouin scattering of crossing intense laser beams is presented Ion trapping alters the dispersion of ion acoustic waves by nonlinearly shifting the normal mode frequency and by reducing the ion Landau damping This in turn can influence the energy transfer between two crossing laser beams in the presence of plasma flows such that stimulated Brillouin scattering (SBS) occurs The same ion trapping physics can influence the saturation of SBS in other circumstances A one-dimensional analytical model is presented along with reasonably successful comparisons of the theory to results from particle simulations and laboratory experiments An analysis of the vulnerability of the National Ignition Facility Inertial Confinement Fusion point design [S W Haan et al, Fusion Sci Technol 41, 164 (2002)] is also presented
95 citations
TL;DR: A self-consistent description of the laser dynamics is proposed that quantitatively reproduces the temporal structure of pulsation and is also attractive for analysis of laser stability and statistics.
Abstract: Backward light scattering can cause passive Q switching in fiber lasers. We propose a self-consistent description of the laser dynamics. Our model quantitatively reproduces the temporal structure of pulsation and is also attractive for analysis of laser stability and statistics. The validity of the model is directly verified in an experiment.
77 citations
TL;DR: In this paper, the authors applied simultaneous phase modulation to the two pump waves so that stimulated Brillouin scattering is suppressed without affecting the generated idler wave, and the signal light was converted from an arbitrary wavelength to another arbitrary one within the entire C-band.
Abstract: Highly efficient tunable wavelength conversion based on nondegenerate fiber four-wave mixing is demonstrated. We apply simultaneous phase modulation to the two pump waves so that stimulated Brillouin scattering is suppressed without affecting the generated idler wave. The signal light is converted from an arbitrary wavelength to another arbitrary one within the entire C-band with a conversion efficiency higher than -10 dB.
75 citations
TL;DR: In this article, the glass transition temperature (Tg) in thin free-standing polymer films of polystyrene (PS) was measured by means of confocal Raman spectroscopy.
Abstract: We report measurements of the glass transition temperature (Tg) in thin free-standing polymer films of polystyrene (PS) by means of confocal Raman spectroscopy. The paper introduces Raman spectroscopy as a novel method for the determination of Tg in polymer thin films. We find excellent agreement between Raman scattering and previously reported values of Tg obtained from either Brillouin scattering or ellipsometry. Further possible applications of the method to more complex conjugated polymers are briefly discussed.
TL;DR: A recently proposed method of measuring the two Brillouin frequencies in a multicompositional fiber core for unambiguously resolving temperature and strain in a distributed sensor is compared with the previously established technique of measure the intensity and frequency of the single BrillouIn peak in a standard single-mode fiber.
Abstract: A recently proposed method of measuring the two Brillouin frequencies in a multicompositional fiber core for unambiguously resolving temperature and strain in a distributed sensor is compared with the previously established technique of measuring the intensity and frequency of the single Brillouin peak in a standard single-mode fiber
TL;DR: A distributed Brillouin scattering sensor has been employed to identify several inner wall cutouts in an end-capped steel pipe by measuring the axial and hoop strain distributions along the outer surface of the pipe.
Abstract: A distributed Brillouin scattering sensor has been employed to identify several inner wall cutouts in an end-capped steel pipe by measuring the axial and hoop strain distributions along the outer surface of the pipe. The locations of structural indentations that constitute 50-60% of the inner pipe wall are found and distinguished by use of their corresponding strain-pressure data. These results are quantified in terms of the fiber orientation, defect size and depth, and behavior relative to those of unperturbed pipe sections.
TL;DR: In this article, isothermal compressibilities and Brillouin sound velocities from the literature were used to separate the compressibility at the glass transition into a high-frequency vibrational and a low-frequency relaxational part.
Abstract: Isothermal compressibilities and Brillouin sound velocities from the literature allow us to separate the compressibility at the glass transition into a high-frequency vibrational and a low-frequency relaxational part. Their ratio shows the linear fragility relation discovered by x-ray Brillouin scattering, though the data bend away from the line at higher fragilities. Using the concept of constrained degrees of freedom, one can show that the vibrational part follows the fragility-independent Lindemann criterion; the fragility dependence seems to stem from the relaxational part. The physical meaning of this finding is discussed.
TL;DR: In this paper, a simple method for all-optical generation of a radio frequency carrier is presented, which is based on stimulated Brillouin scattering (SBS) in an optical fiber and the creation of harmonics by double sideband suppressed carrier modulation.
Abstract: A new simple method for an all-optical generation of a radio frequency carrier is presented, which is based on stimulated Brillouin scattering (SBS) in an optical fibre and the creation of harmonics by double sideband suppressed carrier modulation. For the setup inexpensive standard components of optical telecommunications can be used.
TL;DR: In this paper, the elasticity of grossular-rich Grs87And9Pyp2Alm2 and almandine-rich Alm72Pyp20Sps3Grs3And2 natural garnet single crystals were determined by Brillouin scattering to 11 GPa in a diamond anvil cell.
Abstract: [1] The high-pressure elasticity of grossular-rich Grs87And9Pyp2Alm2 and almandine-rich Alm72Pyp20Sps3Grs3And2 natural garnet single crystals were determined by Brillouin scattering to 11 GPa in a diamond anvil cell. The experiments were carried out using a 16:3:1 methanol-ethanol water mixture as pressure medium. The aggregate moduli as well as their pressure derivatives were obtained by fitting the data to Eulerian finite strain equations. The inversion yields KS0 = 165.0 ± 0.9 GPa, G0 = 104.2 ± 0.3 GPa, (∂KS/∂P)T0 = 3.8 ± 0.2, and (∂G/∂P)0 = 1.1 ± 0.1 for the grossular-rich composition and KS0 = 174.9 ± 1.6 GPa, G0 = 95.6 ± 0.5 GPa, (∂KS/∂P)T0 = 4.7 ± 0.3, and (∂G/∂P)0 = 1.4 ± 0.1 for the almandine-rich garnet. Both individual and aggregate elastic moduli of the two garnets define nearly linear modulus pressure trends. The elastic anisotropy of the garnets increases weakly in magnitude with compression. Isothermal compression curves derived from our results are generally consistent with static compression data under hydrostatic conditions, and the effects of nonhydrostaticity on previous diffraction data can be identified. The pressure derivatives obtained here are generally lower than those reported in high-pressure polycrystalline ultrasonic elasticity studies. In combination with earlier Brillouin scattering data for pyrope, our results allow us to constrain the effect on elastic moduli of Fe2+-Mg2+ substitution in pyrope-almandine, Ca2+-Mg2+ in pyrope-grossular, and Fe3+-Al3+ substitution in andradite-grossular at high pressures. This new data set thus allows us to place improved constraints on the compositional dependence of seismic velocities in the rocks of the upper mantle.
TL;DR: In this article, the authors derived the relation between a figure of merit, M1, for the diffraction efficiency of acousto-optical devices and the Brillouin gain coefficient, gB, and estimated the values of gB and the phonon lifetime for typical As2S3 and As2Se3 chalcogenide glasses.
Abstract: We derived the relation between a figure of merit, M1, for the diffraction efficiency of acousto-optical devices and the Brillouin-gain coefficient, gB We then estimated the values of gB and the phonon lifetime for typical As2S3 and As2Se3 chalcogenide glasses from known acousto-optical parameters We found that the magnitude of gB for these two glasses is greater than 20 times that of fused silica
TL;DR: Sp spontaneous Raman scattering at 1550 nm in ultrasmall silicon-on-insulator (SOI) strip waveguides of 0.098-microm2 cross-sectional area is reported, and the feasibility of high-gain SOI-based fully integrated optical amplifiers is shown.
Abstract: We report spontaneous Raman scattering at 1550 nm in ultrasmall silicon-on-insulator (SOI) strip waveguides of 0.098‐µm2 cross-sectional area. The submicrometer-scale dimensions provide tight optical confinement and, hence, highly efficient Raman scattering with milliwatt-level cw pump powers. The prospect of Raman amplification in such a deeply scaled-down waveguide device in the presence of various loss mechanisms, particularly free-carrier loss that arises from two-photon absorption, is discussed, and the feasibility of high-gain SOI-based fully integrated optical amplifiers is shown.
01 Jan 2004
TL;DR: In this article, the basic concepts of stimulated Brillouin scattering are reviewed together with BrillouIN gain spectrum characterization techniques, system impairments, and applications, and the authors provide a detailed review of the application of these concepts.
Abstract: Basic concepts of stimulated Brillouin scattering are reviewed together with Brillouin gain spectrum characterization techniques, system impairments, and applications
TL;DR: Simultaneous temperature and strain measurement with a distributed Brillouin loss system is proposed by use of the parameters BrillouIn frequency, power, and bandwidth, for PANDA, bow-tie, and tiger polarization-maintaining fibers for the first time to the authors' knowledge.
Abstract: Simultaneous temperature and strain measurement with a distributed Brillouin loss system is proposed by use of the parameters Brillouin frequency, power, and bandwidth, for PANDA, bow-tie, and tiger polarization-maintaining fibers for the first time to our knowledge. The expressions for simultaneous temperature and strain sensing and the maximum errors and rms values of temperature and strain measurements are derived with three combinations of the parameters: (1) power and Brillouin frequency, (2) bandwidth and Brillouin frequency, and (3) bandwidth and Brillouin power. Our experiments demonstrate that simultaneous temperature and strain sensing at 20-cm spatial resolution for Brillouin frequency combined with bandwidth the strain/temperature resolutions are 39 µe/2 °C (PANDA), 126 µe/3 °C (bow tie), and 598 µe/16 °C (tiger); for the Brillouin frequency combined with power the strain/temperature resolutions are 153 µe/8 °C (PANDA) and 237 µe/4 °C (bow tie); and for the bandwidth combined with power the strain/temperature resolutions are 135 µe/38 °C (PANDA) and 195 µe/38 °C (bow tie).
TL;DR: In this paper, the experimental demonstration of the all-fibre passive Q-switching operation of a Raman fiber laser was reported, and the experimental data indicate that Rayleigh, Brillouin and Raman scatterings are all involved in the pulse generation process.
Abstract: The experimental demonstration of the all-fibre passive Q-switching operation of a Raman fibre laser is reported. Giant pulses around 1550 nm with a peak power of 1 kW and pulse duration down to 1 ns were obtained with a 10 km-long fibre cavity pumped by a 2.4 W continuous-wave fibre laser source. Reported experimental data indicate that Rayleigh, Brillouin and Raman scatterings are all involved in the pulse generation process.
TL;DR: A new scheme for the efficient suppression of Brillouin scattering of a single-frequency laser source in a 72 m-long Neodymium-doped fiber amplifier by simultaneous amplification of two seed lasers separated in wavelength by two times the BrillouIn-shift is demonstrated.
Abstract: We demonstrate a new scheme for the efficient suppression of Brillouin scattering of a single-frequency laser source in a 72 m-long Neodymium-doped fiber amplifier by simultaneous amplification of two seed lasers separated in wavelength by two times the Brillouin-shift. This scheme can be independently employed in addition to conventional methods of suppressing stimulated Brillouin scattering enabling further power scaling of existing systems.
TL;DR: In this article, the authors reported the longest sensing range of a distributed temperature change measurement along an optical sensing fiber with single-ended access, based on spontaneous Brillouin scattering and microwave heterodyne detection.
Abstract: We report the longest sensing range of a distributed temperature change measurement along an optical sensing fibre with single-ended access. The technique is based on spontaneous Brillouin scattering and microwave heterodyne detection. The Brillouin frequency shift was used to obtain the distributed temperature change at a range of 100 km with a temperature error of less than 8 °C, and a spatial resolution of 50 m.
TL;DR: In this paper, a multi-wavelength Brillouin/Erbium fiber laser was demonstrated in a linear cavity, which utilized a bi-directional oscillation provided by two fiber loop mirrors at both ends of the laser cavity.
TL;DR: In this article, the authors used Brillouin spectroscopy and CO2 laser-heating to measure sound velocities at high temperatures on single crystals of MgO and Al2O3.
Patent•
22 Jun 2004
TL;DR: In this paper, a distributed fiber sensor based on spontaneous Brillouin scattering is proposed, which uses a single-frequency fiber laser as a source and a cw BrillouIN fiber ring laser as an OLO to optically shift the frequency of the OLO.
Abstract: A distributed fiber sensor based on spontaneous Brillouin scattering uses a single-frequency fiber laser as a source and a cw Brillouin fiber ring laser as an OLO to optically shift the frequency of the OLO to set the Brillouin/OLO beat frequency within the bandwidth of a conventional heterodyne receiver. The distributed fiber sensor is capable of real-time measurement of both temperature and strain.
TL;DR: The study of the laser intensity dependence shows that the secondary ion acoustic waves are correlated with the SBS reflectivity saturation, at a level of a few percent.
Abstract: Thomson scattering (TS) has been used to investigate the two-ion decay instability of ion acoustic waves generated by stimulated Brillouin scattering in an underdense CH plasma. Two complementary TS diagnostics, spectrally and spatially resolved, demonstrate the occurrence of the subharmonic decay of the primary ion acoustic wave into two secondary waves. The study of the laser intensity dependence shows that the secondary ion acoustic waves are correlated with the SBS reflectivity saturation, at a level of a few percent.
TL;DR: A study of the temperature dependence of the Brillouin gain and loss for three different kinds of commercial polarization-maintaining fibers for the first time to the authors' knowledge is reported.
Abstract: We report a study of the temperature dependence of the Brillouin gain and loss for three different kinds of commercial polarization-maintaining fibers for the first time to our knowledge. The Brillouin frequency differences between the fast and slow axes are independent of the temperature, varying between 2.9 and 4.3 MHz. Using 2-ns pulses (equivalent to a spatial resolution of 20 cm), we find that the temperature coefficients for the relative Brillouin power at a wavelength of 1310 nm are 0.26%/C° (panda fiber), 0.23%/C° (bow-tie fiber), and 0.04%/C° (tiger fiber); the temperature coefficients for the Brillouin frequency are 1.37 MHz/C° (panda), 1.66 MHz/C° (tiger), and 2.30 MHz/C° (bow-tie). The temperature coefficients for the Brillouin gain bandwidth are 0.15 MHz/C° (panda), 0.20 MHz/C° (bow-tie), and 0.22 MHz/C° (tiger).
TL;DR: In this article, the dynamical magnetic properties of ultrathin Fe/GaAs(001) films in the thickness range 5-100 A have been studied by in situ Brillouin light scattering.
Abstract: The dynamical magnetic properties of ultrathin Fe/GaAs(001) films in the thickness range 5-100 A have been studied by in situ Brillouin light scattering. Measurement of the spin-wave frequency as a function of both the intensity and the in-plane direction of the applied magnetic field, as well as of the incidence angle of light, enabled us to determine the magnetic parameters of the films. A continnous evolution from uniaxial to biaxial in-plane magnetic anisotropy has been observed with increasing thickness, together with a marked increase of the effective magnetization. Remarkably, we also found that the presence of a Cu capping layer even 1 ML thick, completely suppresses the uniaxial anisotropy in the thinnest samples. This effect is discussed in terms of the possible underlying physical mechanisms.
TL;DR: In this article, a series of thin films and parallel ridges and spacings (gratings) with ridge widths ranging from 180 to 80 nm are presented as a non-contact tool used to quantify the elastic constants in such nanostructures.
Abstract: For a range of applications, polymers are now being patterned into nanometer-sized features. In these applications, the robust mechanical properties of the nanostructures are critical for performance and stability. Brillouin light scattering is presented as a nondestructive, noncontact tool used to quantify the elastic constants in such nanostructures. We demonstrate this through a series of thin films and parallel ridges and spacings (gratings) with ridge widths ranging from 180 to 80 nm. For the set of films and structures presented here, the room-temperature elastic moduli did not change with decreasing film thickness or grating ridge width, and this implied that one-dimensional and two-dimensional confinement-induced changes of the mechanical properties were not significant down to feature sizes of 80 nm. Additionally, Brillouin spectra of submicrometer gratings revealed new modes not present in the spectra of thin films. The origin of these new modes remains unclear. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1106–1113, 2004