Multi-parameter sensor based on cascaded multicore FBGs and an FPI for bending, temperature and pressure measurements

A multi-parameter sensor based on cascaded multi-core fiber Bragg grating (FBG) and Fabry-Perot interferometer (FPI) is proposed. The sensor consists of a single-mode fiber (SMF), a four-core fiber (FCF), and a hollow fiber (HCF) filled with polydimethylsiloxane. The HCF is fused at the end of the FCF to form an FPI. Through thermal diffusion technology (TDT), the all-fiber single-channel measurement of the sensor is realized. The FCF FBGs have a maximum sensitivity of 96.33 pm/m−1 for vector bending and 9.8 pm/°C for temperature. The FPI is capable of measuring temperature and pressure with sensitivities of 1621.2 pm/°C and 6500.0 pm/MPa, respectively. Consequently, a set of wavelength shift equations is derived to simultaneously measure vector bending, temperature, and pressure. The proposed multi-parameter sensor offers the advantages of high integration and reduced cross-talk, making it a promising candidate for applications such as environmental monitoring, structural health monitoring, and wearable artificial electronics.