InGaSn-assisted in-fiber Fabry-Perot temperature sensor with ultra-high sensitivity.

In this paper, we proposed an in-fiber Fabry-Perot temperature sensor which filled with Indium gallium stannum (InGaSn) alloy. By splicing a single-mode fiber axially with hollow-core fibers (HCFs) of varying inner diameters, a cavity of the Fabry-Perot interferometer (FPI) structure is formed. Assisted by liquid metal with fluidity and high thermal expansivity, subtle temperature fluctuations are converted into variations in the interferometric cavity length which leads to a significant spectral drift.

Highly sensitive vector bending sensor based on an embedded multimode D-shaped LPFG.

In this letter, a highly sensitive bending sensor based on an embedded multimode D-shaped long period fiber grating (EMD-LPFG) is proposed. The novel sensor is applied to carry out vector bending measurement. The proposed LPFG is fabricated by polishing on the prepared structure which is formed by periodically splicing between single mode fiber (SMF) and multimode fiber (MMF).