We demonstrate a new type of fiber optic bend sensor with a hybrid structure made up of a long period grating (LPG) and a tilted fiber Bragg grating (TFBG). The sensing mechanism is based on the spectrum of power transfers between the core and cladding modes from a TFBG located downstream from a LPG. We show that the curvature of a beam can be determined by the reflected power difference between the core mode and the recoupled cladding modes. We further provide design rules for the LPG and TFBG to optimize and linearize the sensor response. In addition, the temperature cross-sensitivities of this configuration are also investigated for two different types of fiber.

Additional Metadata
Keywords Bend sensor, Cladding mode recoupling, Curvature measurement, Long period grating, Tilted fiber Bragg grating
Contributor Canada Research Chairs Program, LxData Inc.
Funder Natural Sciences and Engineering Research Council of Canada
Persistent URL dx.doi.org/10.1016/j.optcom.2010.03.013
Journal Optics Communications
Shao, L.-Y, Laronche, A, Smietana, M. (Mateusz), Mikulic, P. (Predrag), Bock, W.J. (Wojtek J.), & Albert, J. (2010). Highly sensitive bend sensor with hybrid long-period and tilted fiber Bragg grating. Optics Communications, 283(13), 2690–2694. doi:10.1016/j.optcom.2010.03.013