Multiparameter Sensor Based on DCF Composite Tapered Structure Cascaded LPFGs for the Simultaneous Measurement of Refractive Index, Temperature, and Axial Strain

Multiparameter measurement depending on the cavity-length differentiation characteristics of a microfiber Fabry–Perot interferometer

“…Usually, FBG sensors use only wavelength as the means of detection for a measured parameter, which limits their ability to directly distinguish between different parameters and can easily lead to cross-interference [21,22]. To overcome this problem, researchers have been exploring new approaches and structures, such as the use of multi-grating structures [23][24][25], special fiber structures [26][27][28][29] fiber Fabry-Perot interference [30][31][32][33] structures, polymer coatings [34][35][36][37], and multi-sensor networks [38][39][40] to improve the multiparameter measurement capability and cross-interference resistance of FBG sensors. For example, Fu et al [25] proposed a fiber sensor based on a cascaded long-period fiber grating with a double-clad fiber composite tapered structure.…”

“…To overcome this problem, researchers have been exploring new approaches and structures, such as the use of multi-grating structures [23][24][25], special fiber structures [26][27][28][29] fiber Fabry-Perot interference [30][31][32][33] structures, polymer coatings [34][35][36][37], and multi-sensor networks [38][39][40] to improve the multiparameter measurement capability and cross-interference resistance of FBG sensors. For example, Fu et al [25] proposed a fiber sensor based on a cascaded long-period fiber grating with a double-clad fiber composite tapered structure. The transmission spectrum of this sensor contained three resonance peaks that can be used to simultaneously measure refractive index, temperature, and axial strain based on the different sensitivities of the resonance peaks to different parameters.…”