A novel double-parameters optical fiber sensor based on spherical structure and multimode fiber has been proposed and experimentally demonstrated. The output signal is a series of interference superposition, external parameters can be measured by monitoring the spectral characteristics of interference dips.
The interesting properties of the sensor include good operation linearity and high sensitivities. The sensitivities of temperature and refractive index can reach up to 0.131 nm/°C and 111.14 nm/RIU, respectively. Simultaneous measurement of temperature and refractive index can be realized according to the different spectral responses.