Based on the configuration of surface plasmon resonance (SPR) sensor, the SPR sensor model is set up, and the thermo-properties of various parts in the model are discussed. The thermo-characteristics of SPR spectra in wavelength interrogation and angular interrogation are investigated. Results show that thermo-optic and dispersion effects in the model deteriorate the sensitivity of SPR sensor, especially the thermo-optic effects. Mathematical expression is established to describe the resonance wavelength or angle, which is dependent of temperature. It demonstrates that the thermo-property of sensing medium excites the fluctuation of resonance wavelength or angle more intensely than that of the substrate or metal film in 1–2 orders. Our theoretical research is consistent with the previous experimental results.

Attenuated total reflection (ATR) ratio is usually utilized to study the properties of surface plasmon resonance (SPR) sensors. The relationship between normalized light intensity and ATR ratio is investigated, and a modification coefficient is put forward to describe the relationship. A mathematical expression is built up for the coefficient based on Fresnel principle. The result shows that the ATR ratio, which cannot be measured directly in experiments, can be determined with the coefficient and the normalized intensity of light. The characteristic of the coefficient is also discussed.

Influence of temperature on measurement of surface plasmon resonance (SPR) sensor was investigated. Samples with various concentrations of NaCl were tested at different temperatures. It was shown that if the affection of temperature could be neglected, measurement precision of salt solution was 0.028 wt.-%. But measurement error of salinity caused by temperature was 0.53 wt.-% in average when the temperature drift was 1 Celsius degree. To reduce the error, a double-cell SPR sensor with salt solution and distilled water flowing respectively and at the same temperature was implemented.