Fig. 1. Sensor structure. (a) Schematic diagram of sensor structure; (b) microscope view of tapered region; (c) microscope view of fusion collapse region; (d) microscope view of PCF endface

Fig. 2. Reflectance spectra of sensor. (a) Reflectance spectrum of tapered PS-FBG; (b) reflectance spectra before and after silver plating; (c) MZI reflection spectra with different PCF lengths; (d) reflection spectrum of complete hybrid structure device

Fig. 3. Mode field distribution and energy transfer diagram of MZI beam propagation process

Fig. 4. Spectra of strain sensing experiments. (a) Spectra of devices under different strains; (b) MZI strain response fitting curve; (c) spectra of tapered PS-FBG under different strains; (d) fitting curves of strain response of tapered PS-FBG

Fig. 5. Spectra of temperature sensing experiments. (a) Spectra of devices under different temperatures; (b) MZI temperature response fitting curve; (c) spectra of tapered PS-FBG under different temperatures; (d) fitting curves of tapered PS-FBG temperature response

Fig. 6. Spectra of refractive index sensing experiments. (a) Spectra of devices under different refractive indexes; (b) refractive index response fitting curve of MZI