Characteristics of a capillary single core fiber based on SPR for hydraulic pressure sensing

D-Shape hollow capillary single core optical fiber sensor based on Surface Plasmon Resonance (SPR) has been proposed in this paper for hydraulic pressure sensing. For the proposed fiber, there is a large air hole on the cross section and a D-type platform is fabricated adjacent the Ge-doped fiber core. A thin dielectric layer is located on the inner surface of the central air hole, it is used to improve the sensitivity of hydraulic pressure sensing. A gold-dielectric stacking layer is located on the dielectric layer surface to support SPR. Using Finite Element Method, simulation results show that the sensitivity of the sensor can reach 240 pm/MPa in the range of 0 to 50 MPa, compared with the single-gold-layer structure, the sensing sensitivity of the dielectric-gold-layer structure sensor is increased by more than 3.4 times. Moreover, the proposed sensor greatly improves the measurement range of existing pressure sensors based on SPR effect, and has a good linear sensing sensitivity.