Cascaded dual-channel fiber SPR temperature sensor based on liquid and solid encapsulations

In order to control the working wavelength range of the fiber surface plasmon resonance (SPR) temperature sensor and realize the wavelength division multiplexing type multi-channel fiber SPR temperature sensor, by comprehensively investigating the influence of liquids with different thermal-optical coefficients and solid packaging materials on the performance of fiber SPR temperature sensor, a dual-channel fiber SPR temperature sensor based on liquid-solid cascade encapsulation was designed and fabricated. The liquid temperature sensing stage encapsulated in capillary worked in 616.03 nm-639.05 nm band, the solid sensing stage coated with pouring sealant worked in 719.37 nm-825.27 nm band, and the two stages were cascaded to form a fiber dual-channel temperature sensor. The testing results indicated that when the temperature range was 35 ℃-95 ℃, the sensitivity of two-stage temperature detection was -0.384 nm/℃ and -1.765 nm/℃ respectively. The proposed fiber sensor has simple fabrication and excellent performance which can be widely used in various fields of dual-channel temperature measurement and temperature compensation.