Tunable fiber Bragg grating combined with microactuator

A tunable fiber Bragg grating combined with a microactuator is described. The electromagnetically driven microactuator realizes the mechanism for twisting the fiber, and the strain is generated inside the fiber Bragg grating. The twisting-type microactuator is prepared by bulk Si micromachining, and the optical fiber is thinned down to 30 μm diameter at the Bragg grating region for reducing the torsional rigidity of the fiber and for confining the strain. The strain changes the refractive index of the optical fiber due to the photoelastic effect. The twisting angle of the fiber reaches over 6 deg and the redshift of the Bragg wavelength up to 0.25 nm is demonstrated.