Application Research Of TDM Multichannel Optical Fiber SPR Sensing System

As a popular surface analysis method,surface plasmon resonance is used to detect the change of refractive index or thickness of the adsorption layer on or near the active surface of SPR,and has the advantages of high sensitivity and high reliability.With the development of SPR sensing technology,multi-channel SPR sensors have been widely used due to their potential use in the field of biochemical analysis.The advantage is that multi-parameter multiconcentration simultaneous detection,and can reduce the system jitter by setting the reference channel or Errors caused by other external factors,the detection system is smaller in size,reducing the use of core devices and reducing costs.TDM technology is a common method for realizing multi-channel sensing.For SPR sensors using wavelength modulation,TDM technology is generally used to "parallel" and then perform spectral analysis,or optical switches are used to route optical paths and then through spectral analysis to complete system construction.In this paper,two fiber-optic SPR sensing systems are constructed.One uses a dual-source automatic switching optical path to implement TDM dual-channel;the other uses a custom 1×4 optical switch to route light to implement TDM four-channel.Through these two methods,the TDM multi-channel sensing system is built,and the sensing performance and biochemical detection performance of the two systems are experimentally verified.The specific papers are as follows:Firstly,the sensing characteristics of SPR technology are introduced,and the purpose and significance of this paper are expounded.The theoretical basis of optical fiber SPR sensing technology is introduced.Secondly,the TDM dual-channel fiber SPR sensing system is constructed by using the light source with shutter.The system is a small and self-referential fiber SPR instrument based on TDM technology.It uses two light source inputs to control the optical path switching through automatic shutter,and activates two independent functions.The optical path ensures that the spectral interrogation between the two channels does not interfere with each other to achieve TDM dual channel.It can compensate the refractive index change caused by temperature fluctuation or other external disturbances in real time,and detect different concentrations of NaCl solution,modify the surface of the sensor,use its high sensitivity and selectivity for glucose concentration detection,and use 2-aminoethanethiol(AET)and pphenylphenylboronic acid(PMBA)monolayer functionalized fiber SPR sensors for glucose recognition at physiological pH and then enhanced sensor response via gold nanoparticles(AuNPs).Finally,based on the two-channel detection system,the optical path is realized by 1×4 optical switch,and the four-channel wavelength modulation optical fiber SPR detection system is built based on TDM technology.The detection system is suitable for multi-channel liquid refractive index and biochemical self-reference measurement field..The detecting light source is connected to the multimode fiber optical switch,and the serial port on the optical switch is sent by the computer to control the optical switch to align the designated optical path to realize the TDM four-channel detection.Different concentrations of NaCl solution were detected for the sensing performance of the sensing system;the biochemical detection performance of the system was verified,and the rapid IgG detection experiment was carried out by biochemically modifying the surface of the sensor.