Sensitivity Improvement in Fiber Bragg Grating Sensors Using All-Fiber Weak Value Amplification Based on Optical Attenuation

A new method for all-fiber weak value amplification (WVA) based on optical attenuation is proposed, and we theoretically and experimentally demonstrated improved sensitivity of the centroid shift of a fiber Bragg grating (FBG) sensor to an external perturbation change. In the proposed WVA method, we figure out that optical attenuation plays an important role in determining the amplification factor for improving the sensitivity of the centroid shift of the FBG sensor to external perturbations. The amplification factor and the centroid shift based on variations in the external perturbation are theoretically analyzed, which are related to optical attenuation. Controlling the optical attenuation to optimize the amplification factor can successfully improve the sensitivity of the centroid shift to strain and temperature. When the optical attenuation was changed from 9 to 3 dB, the strain and the temperature sensitivities of the centroid shift improved from 1.09 to 2.40 pm/με and 15.63 pm/°C to 38.62 pm/°C.