title: Phase-based Bragg intragrating distributed strain sensor.
abstract: A strain-distribution sensing technique based on the measurement of the phase spectrum of the reflected light from a fiber-optic Bragg grating is described. When a grating is subject to a strain gradient, the grating will experience a chirp and therefore the resonant wavelength will vary along the grating, causing wavelength-dependent penetration depth. Because the group delay for each wavelength component is related to its penetration depth and the resonant wavelength is determined by strain, a measured phase spectrum can then indicate the local strain as a function of location within the grating. This phase-based Bragg grating sensing technique offers a powerful new means for studying some important effects over a few millimeters or centimeters in smart structures.
authors.forename: S
authors.initials: S
authors.lastname: Huang
authors.forename: M M
authors.initials: MM
authors.lastname: Ohn
authors.forename: R M
authors.initials: RM
authors.lastname: Measures