Optical fiber sensor determination of the water salinity based on surface plasmon resonance

In this thesis, the detail design of the system was discussed, including inspection system and the surface plasmon resonance (SPR) sensors based on taper technology. An Optical Fiber Sensor comparison scheme based on SPR detection of measuring the salinity of water sample was formulated to meet some practice requirements,such as accuracy, fast, small size and high sensitivity RIU(Refractive index units). The influence of each parameter on the optical fiber SPR sensor system design was simulated by using Matlab and C++, which gave a theoretical base for the choice of suitable parameters in device design. Then a new detection system, combing with optics, mechanism and electronic technology, was designed. According to the taper technology and mode field analysis theory, result of preliminary experiment shows that this device is basically met the design requirements such as compact, portable, good linearity and highly RIU. SPR experiments about NACL-water mixture with different salinity are implemented in this new device, and experimental results show that accurate detection on single sample can be achieved, and the detecting of the resonance wavelength differentiation is 0.15 nm, moreover, the detecting results has high linearity and good stability, and the refraction index(RI) detecting deviation is less than 0.002.