title: Fiber Bragg grating location by a side-scatter technique based on cladding-mode coupling.
abstract: At wavelengths slightly shorter than the normal resonance for a fiber Bragg grating, radiation can be coupled into cladding and radiation modes that become visible external to the fiber. We describe experimental measurements on a fiber Bragg grating under broadband illumination, showing the axial variation and angular distribution of side-scattered radiation. The scattering signal can locate the grating position subject to an offset in the backscatter direction. The spectrum of scattered radiation is consistent with a published theoretical model of mode coupling by a grating in a finite cladding fiber.
authors.affiliation: School of Engineering and Physical Science, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom. r.r.j.maier@hw.ac.uk
authors.forename: Robert R
authors.initials: RR
authors.lastname: Maier
authors.forename: James S
authors.initials: JS
authors.lastname: Barton
authors.forename: Julian D
authors.initials: JD
authors.lastname: Jones