Multi-channel And Practical Research Of Optical Fiber Surface Plasmon Resonance Sensor

Surface plasmon resonance(SPR)sensing technology as a novel optoelectronic sensing technique,which is widely used in biological reaction detection,drug development,food safety etc.The optical fiber SPR sensor based on the SPR mechanism has many advantages such as small size,strong anti-interference ability,and real-time online transmission at long distance.Optical fiber SPR sensor is an inevitable trend in the development of SPR sensing technology,and it is a concrete manifestation of the realization of integration,miniaturization,high sensitivity and high reliability of the sensor.In this paper,we focus on the problems of multi-channel measurement difficulties and practical development difficulties of optical fiber SPR sensors,and we mainly do the following researches:1.We employ the bare fiber grinding technology to grind the six circularly symmetric distributed cores of the seven-core fiber to realize the three channel SPR sensing and testing.A reflective SPR three-channel sensor base on time division multiplexing technology is realized.Besides that,we propose a SPR multi-channel segmented detection method base on seven-core optical fiber.By using three sensing probes with different grinding angles to detect solutions with different refractive index ranges,which will reduce the requirements of the light source and the spectrometer and lays the foundation for SPR experimental research with narrow bandwidth and high stability light source spectrometer.The proposed sensor realizes the ultra-high sensitivity with the large detection range of 1.333-1.395 firstly,and the average sensitivity reaches 7387.1nm /RIU,the highest sensitivity reaches 8502.5nm /RIU.2.We employ the bare fiber grinding technology and fiber offset welding technology to fabricate a double tilt angle SPR dual channel sensor based on wavelength division multiplexing technology.By employing thick-core plastic-clad multimode optical fiber and a thick-core glass-clad multimode optical fiber,the sensor structure is cleverly designed.The plastic-clad optical fiber is designed as a horizontal SPR sensing zone and a wedge-shaped SPR sensing zone.According to experiment results,the two-stage average sensitivity of the dual-channel SPR sensor is 1961 nm/RIU and 4519 nm/RIU,respectively.3.We splice single-mode fiber eccentrically with single-mode fiber,step multi-mode fiber,and graded multi-mode fiber,respectively.The light source light is directly coupled into three types optical fibers,and a 50 nm sensing gold film is plated on the surface of the three optical fiber claddings,a practical SPR sensor structure is realized without removing the optical fiber cladding.By one ordinary optical fiber welding machine,the evanescent wave is easily obtained,which greatly simplifies the production of the sensor probe and promotes the practical development of optical fiber SPR sensors.