An intracore Bragg grating written on a photosensitive fiber core is used for strain measurement in composite specimens under load. The strain information is directly related to the absolute change in the Bragg-reflected wavelength. Fiber Bragg grating (FBG) sensors (fibers with intracore gratings) are thus sensitive to strain that is caused by changes in temperature as well as to load-induced changes. Thus these sensors can be made to be independent of source intensity variations and losses. FBG sensors used for load-induced strain sensing in composite structures and the effects of temperature on them are discussed. A detailed account of the use of such embedded structures as self-monitoring nondestructive testing devices is given.
© 2001 Optical Society of America
(050.0050) Diffraction and gratings : Diffraction and gratings
(050.2770) Diffraction and gratings : Gratings
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
V. M. Murukeshan, P. Y. Chan, Lin Seng Ong, and A. Asundi, "Intracore Fiber Bragg Gratings for Strain Measurement in Embedded Composite Structures," Appl. Opt. 40, 145-149 (2001)