Phase shift chirped fiber Bragg grating based distributed strain and position sensing

Abstract

A corresponding peak appears on the transmission spectrum, when the micro-strain is induced in a chirped fiber Bragg grating (CFBG). The center wavelength of the peak is sensitive to the location and magnitude of the strain, thus, the CFBG can be used in distributed strain and strain-points precise position sensing. The depth and center wavelength of the peak are determined by the magnitude and location of the strain. The cascaded CFBGs under different center wavelengths can realize the distributed strain and strain-point precise positioning. Considering the fact that the depth and center wavelength of the peak are related to the magnitude and location of strain, a theoretical model is established with V-I transmission matrix formalism. Theoretically, cascaded CFGBs can realize accurately the positioning of micron-scale. Experimentally, two CFBGs are cascaded and a sensitivity of 0.19 pm/ is obtained. The proposed precise position sensing can be applied to the fields of advanced manufacturing, precision machining, aerospace, railway-system, etc.