2011 Fiscal Year Final Research Report

Research on the Second Bragg Diffraction from Brillouin Dynamic Grating in an Optical Fiber and its Sensing Application

Research Project

Project/Area Number	23656261
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Measurement engineering
Research Institution	The University of Tokyo
Principal Investigator	HOTATE Kazuo 東京大学, 大学院・工学系研究科, 教授 (60126159)
Co-Investigator(Renkei-kenkyūsha)	HE Zuyuan 東京大学, 大学院・工学系研究科, 特任教授 (70322047) KISHI Masato 東京大学, 大学院・工学系研究科, 助教 (00150285)
Project Period (FY)	2011
Keywords	計測システム / 光ファイバセンサ / スマート材料・構造 / 分布型センシング / 防災危機・管理技術
Research Abstract	It has been tried to observe the second Bragg diffraction from the Brillouin dynamic grating(BDG), for which our group had discovered to be associated with stimulated Brillouin scattering. Theoretical consideration on this phenomenon has also been performed. At first, the second Bragg diffraction from a FBG has successfully been observed at the wavelength of 6nm shorter than half the first diffraction wavelength, which has met well with the theoretical estimation. It has also been calculated that the spectral width of the BDG second diffraction is narrower than 10MHz, and the experimental setup to meet the requirements has been constructed. A possible spectrum has been observed around 779. 94nm, though it has not yet been confirmed because of the repeatability.