Research On Surface Plasmon Rsonance Temperature Sensor Based On Microstructured Optical Fiber

Microstructured optical fiber has attracted more and more scholars to study it in the fields of optical fiber communication and optical fiber sensing for its unique structure and characteristics.Surface plasmon resonance technology is very sensitive to changes in refractive index of metal surfaces,which makes it used in many sensing devices.Recently,microstructured optical fibers have been actively studied in surface plasmon resonance sensing.In comparison with other configurations such as prisms and conventional optical fibers,benefits of the microstructured optical fibers are that they can realize desirable guiding properties and the convenience of reasonable mechanical strength.This article mainly introduces the microstructured optical fiber surface plasmon resonance sensor.Aiming at the problem that the sensor manufacturing process is too complicated and the challenge of high refractive index detection,the D-type and the slotted microstructured optical fiber are mainly introduced,and the following three microstructured optical fiber based surface plasmon resonance temperature sensors are proposed.(1)An all-solid D-type microstructured optical fiber surface plasmon resonance sensor is designed,which can simultaneously realize refractive index and temperature sensing.The refractive index sensing portion is formed by coating the silver film on the plane of the D-type structure of the fiber,and the temperature sensing portion is constructed by filling the silver nanowire and the liquid mixture(sensing medium)into the only air hole of the microstructured optical fiber.This design can support two independent peaks in the x and y polarizations which can be used to distinguish the refractive index and temperature changes.The effects of the coupling characteristic and sensing performance of the sensor and the position of the silver nanowire in the air hole on the sensor were studied.The numerical results show that when the refractive index of the sensing medium is in the range of 1.41 to1.42,the maximum sensitivity of the sensor is 10 300 nm/RIU,and the maximal temperature sensitivity is 4.22 nm/? in the range of-3 ? to 15 ?.(2)A surface plasmon resonance sensor based on the D-type side-opened hollow core microstructured optical fiber is proposed,and the sensor is coated with a gold film on the surface of the D-type profile.When the sensor is completely immersed in the analyte solution,the core will be filled with the analyte and the metal layer in the D-type plane will be in contact with the analyte.When the sensor is partially immersed in the analyte solution,only the core is filled with the analyte.For these two cases,the results of research and analysis show that the proposed sensor can detect the high refractive index analyte and shows higher sensitivity when only the core portion is immersed into the analyte.In this way,this sensor can provide the ability of anti-interference from the metal coating.At the same time,the sensor can be easily coated with a metal film and offers the possibility of real-time sensing.(3)A surface plasmon resonance temperature sensor based on the side opening hollow-core microstructure optical fiber is studied,which makes it easier to fill the sensing medium.In addition,the sensor can detect high refractive index sensing media.The coupling characteristic,sensing performance and fabrication tolerance of the sensor are analyzed by using the finite element method.The simulation results indicate that the maximum sensitivity are 3.21 nm/? for the x-polarized core mode in the temperature range of 13.27–50.99 ?,and 4.98 nm/? for the y-polarized core mode in the temperature range of 14.55–51.19 ?,when benzene is used as the sensing medium.The sensor also shows a good stability in the range of ±10% fabrication tolerance.