Principles and realizations of FBG wavelength tuning with elastic beams

The general principles and realizations of FBG wavelength tuning with elastic beams are proposed and demonstrated.Theories and experiments show that when displacement at the center point of simple beams,deflection of cantilever beams and torsion strain of torsion beams are relatively small,Bragg wavelength shifts of sensing FBGs have linear relationship with applied external stress,lateral displacement,torque and torsional angles,respectively.The experimental results indicate that the curvature sensitivity of the simple beam is 1.65 nm/m-1,the displacement sensitivity of the equivalent-strain cantilever beam is 4.4 cm/kg and the torque and torsional angle sensitivities of the torsion beam are 6.27 nm/Nm and 0.086 7 nm/degree,respectively.