Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers

Brillouin light scattering describes the diffraction of light waves by acoustic phonons, originating from random thermal fluctuations inside a transparent body, or by coherent acoustic waves, generated by a transducer or from the interference of two frequency-detuned optical waves. In experiments wi...

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Main Authors: Vincent Laude, Jean-Charles Beugnot
Format: Article
Language:English
Published: MDPI AG 2018-06-01
Series:Applied Sciences
Subjects:
Online Access:http://www.mdpi.com/2076-3417/8/6/907
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spelling doaj-ed1a991a934f4c67b46913334584ba742020-11-25T01:12:59ZengMDPI AGApplied Sciences2076-34172018-06-018690710.3390/app8060907app8060907Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical FibersVincent Laude0Jean-Charles Beugnot1Institut FEMTO-ST, Université Bourgogne Franche-Comté, CNRS, 25030 Besançon, FranceInstitut FEMTO-ST, Université Bourgogne Franche-Comté, CNRS, 25030 Besançon, FranceBrillouin light scattering describes the diffraction of light waves by acoustic phonons, originating from random thermal fluctuations inside a transparent body, or by coherent acoustic waves, generated by a transducer or from the interference of two frequency-detuned optical waves. In experiments with optical fibers, it is generally found that the spontaneous Brillouin spectrum has the same frequency dependence as the coherent Brillouin gain. We examine the origin of this similarity between apparently different physical situations. We specifically solve the elastodynamic equation, giving displacements inside the body, under a stochastic Langevin excitation and in response to a coherent optical force. It is emphasized that phase matching is responsible for temporal and spatial frequency-domain filtering of the excitation, leading in either case to the excitation of a Lorentzian frequency response solely determined by elastic loss.http://www.mdpi.com/2076-3417/8/6/907stimulated Brillouin scatteringnoise initiationspontaneous Brillouin scatteringBrillouin gain
collection DOAJ
language English
format Article
sources DOAJ
author Vincent Laude
Jean-Charles Beugnot
spellingShingle Vincent Laude
Jean-Charles Beugnot
Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
Applied Sciences
stimulated Brillouin scattering
noise initiation
spontaneous Brillouin scattering
Brillouin gain
author_facet Vincent Laude
Jean-Charles Beugnot
author_sort Vincent Laude
title Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
title_short Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
title_full Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
title_fullStr Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
title_full_unstemmed Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers
title_sort spontaneous brillouin scattering spectrum and coherent brillouin gain in optical fibers
publisher MDPI AG
series Applied Sciences
issn 2076-3417
publishDate 2018-06-01
description Brillouin light scattering describes the diffraction of light waves by acoustic phonons, originating from random thermal fluctuations inside a transparent body, or by coherent acoustic waves, generated by a transducer or from the interference of two frequency-detuned optical waves. In experiments with optical fibers, it is generally found that the spontaneous Brillouin spectrum has the same frequency dependence as the coherent Brillouin gain. We examine the origin of this similarity between apparently different physical situations. We specifically solve the elastodynamic equation, giving displacements inside the body, under a stochastic Langevin excitation and in response to a coherent optical force. It is emphasized that phase matching is responsible for temporal and spatial frequency-domain filtering of the excitation, leading in either case to the excitation of a Lorentzian frequency response solely determined by elastic loss.
topic stimulated Brillouin scattering
noise initiation
spontaneous Brillouin scattering
Brillouin gain
url http://www.mdpi.com/2076-3417/8/6/907
work_keys_str_mv AT vincentlaude spontaneousbrillouinscatteringspectrumandcoherentbrillouingaininopticalfibers
AT jeancharlesbeugnot spontaneousbrillouinscatteringspectrumandcoherentbrillouingaininopticalfibers
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