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.
© 2004 Optical Society of America
(060.2300) Fiber optics and optical communications : Fiber measurements
(060.2310) Fiber optics and optical communications : Fiber optics
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(230.1480) Optical devices : Bragg reflectors
(290.5820) Scattering : Scattering measurements
Robert R. J. Maier, James S. Barton, and Julian D. C. Jones, "Fiber Bragg Grating Location by a Side-Scatter Technique Based on Cladding-Mode Coupling," Appl. Opt. 43, 3310-3314 (2004)