▎ 摘　　要

We propose a highly sensitive surface plasmon resonance (SPR) sensor based on D-shaped with a silver-graphene layer. The sensing characteristics is numerically analyzed by the finite-element method. An ultra-high spectral sensitivity of 58650 nm/refractive index unit (RIU) with high linearity is achieved in the sensing range between 1.42 and 1.44, thereby resulting in a high resolution of 2 x 10(-6) RIU as a sensor. The influence of thickness of silver and graphene layer on sensing performance have been investigated and analyzed in detail. The D-shaped structure of the fiber helps in improving the phase matching, and the graphene layer can provides enhancing its sensing performance effectively. Results have potential application for designing high-performance optical fiber SPR sensors. (C) 2017 Elsevier GmbH. All rights reserved.