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Song, Kwang Yong,Zou, Weiwen,He, Zuyuan,Hotate, Kazuo Optical Society of America 2009 Optics letters Vol.34 No.9
<P>We demonstrate the distributed measurement of Brillouin dynamic grating spectra in a polarization-maintaining fiber based on time-domain analysis. Local reflection spectra of the Brillouin dynamic grating are acquired by synchronized propagation of the pump and the probe pulses based on the map of the Brillouin frequency distribution. Large temperature sensitivity as high as -50.9 MHz/ degrees C is observed with 2 m spatial resolution in 100 m range.</P>
Applications of Brillouin Dynamic Grating to Distributed Fiber Sensors
Kwang Yong Song,Hotate, Kazuo,Weiwen Zou,Zuyuan He IEEE 2017 Journal of Lightwave Technology Vol.35 No.16
<P>In the process of stimulated Brillouin scattering (SBS), acoustic waves are generated by the interference of counterpropagating optical waves via electrostriction effect. These acoustic waves not only stimulate the Brillouin scattering process, but can also play a role of moving Bragg reflector for another optical wave when a proper phase-matching condition is satisfied between the interacting optical waves. Brillouin dynamic grating (BDG) represents this secondary role of the acoustic wave, which shows a unique reflection spectrum, called BDG spectrum. The BDG spectrum generally shows higher sensitivity to the change of physical variables, such as temperature and strain than ordinary Brillouin gain spectrum (BGS), and also provides information on the waveguide parameters, such as polarization or modal birefringence with high accuracy. This paper reviews the operation principle of BDG under various conditions and the research progresses on its application to distributed fiber sensors.</P>