College of Electronic&Information Engineering;
Chongqing Three Gorges University;
Chongqing 404100;
China;
National Engineering Laboratory for Fiber Optic Sensing Technology;
Wuhan University of Technology;
Wuhan 430070;
China;
Key Laboratory of In-fiber Integrated Optics;
Ministry of Education of China;
Harbin Engineering University;
Harbin 150001;
China;
coaxial dual-waveguide; optical fiber D structure; optical fiber microsphere structure; dual-channel fiber-optic surface plasmon resonance(SPR)sensor;