Compact vector bending sensor based on two orthogonal tilted fiber bragg gratings

A novel optic fiber sensing head is proposed and demonstrated for vector bending measurement. Two weakly titled Bragg gratings are spliced together with tilt planes at nearly 90 degree, followed by a cleaved end mirror. Two groups of resonances in reflection have different bending behaviors, which allows for unique bending orientation measurement from 0 to 180 degree.