A High Sensitivity Surface Plasmon Resonance D-Shaped Fiber Sensor Based on a Waveguide-Coupled Bimetallic Structure: Modeling and Optimization

A D-shaped optical fiber surface plasmon resonance sensor based on waveguide coupled mode using a bimetallic structure is proposed. Finite difference time domain method is used to examine the proposed structure and to improve its sensitivity. Maximum sensitivity of about 6140.2 nm/RIU is achieved. The sensor has some advantages, including high speed and sensitivity, easy construction, easy connection to other devices due to high numerical aperture optical fiber, small size, and in vivo test capability.