FBGs based multicore fiber curvature sensor interrogation using microwave photonics filtering techniques

A high-resolution and temperature-insensitive interrogation scheme for fiber Bragg grating (FBG) based multicore fiber curvature sensor using microwave photonics filtering techniques is proposed and verified by experimental demonstration. The principle of operation exploited for curvature interrogation is based on monitoring the notch frequency shift of a two-tap microwave photonics filter (MPF), which is formed by combining two reflected sample signals from the two FBGs inscribed in multicore fiber (MCF) and a dispersion device. The proposed interrogation scheme with the sensitivity of 92 MHz/m^-1 is achieved, whilst it is naturally insensitive to any temperature variations.