Simulations and experiments on D-type SPR fiber sensor by using the intensity and phase methods

-- For improving the sensitivity of a D-type SPR fiber sensor, we simulated the optimum parameters , such as, the thickness of coatings, the length of sensor, and the angle of incidence for different ranges of refractive index. These simulations are based on SPR theory and the intensity and phase methods. It is clearly that, the sensitivity is improved by increasing the length of sensor and/or the thickness of the gold film. And the sensitivity of the phase method is higher than the intensity method by two orders. It is used to detect the refractive index or concentration of gas or liquid in real-time, and it has some merits, such as, small, simple, cheaper, and in vivo test. Keywords : surface plasmon resonance (SPR), fiber sensor 1. INTRODUCTION SPR fiber sensor is very useful in many applications in resent years 1-4 , such as, physical, chemical, biophotonics, etc. Although the sensitivity is not as high as that of the SPR prism sensor, however, owing to its merits such as, low cost, smaller tested volume, convenient to operation, in-vivo testing, it is also attention-getting in the future. There are several types of optical fiber sensor (OFS) based on surface plasmon resonance had been proposed