Study On Glucose Sensing Characteristics Based On Multimode Interference Optical Fiber Sensor

Compared with the traditional biosensor,optical fiber biosensor(OFBS)has the advantages of small volume,anti electromagnetic interference,corrosion resistance,low cost and so on.In recent years,it has developed rapidly in the field of sensing and is used in many fields,such as biology,medicine,food,military and so on.Glucose plays an important role in the field of biomedicine,and it is the main energy supply substance for human and other animals.Therefore,it is very important for the detection of glucose concentration.Based on this,the principle of multimode interference and the SMS type optical fiber structure(single mode multimode single mode)sensor are introduced in detail in this paper.Then the transmission light field distribution of the SMS type fiber structure is simulated by using the beam propagation method.The transmission spectrum of the SMS type fiber sensor will be changed by changing the parameters of multimode fiber.Finally,We build the SMS optical fiber glucose sensor system,and carry out the refractive index experiment and glucose sensing experiment of the sensor.The main contents in this article are as follows:1.Introduce the theoretical methods of glucose sensors and their applications in sensing field,and analyzes the characteristics of each sensor.The development of SMS fiber sensor based on multi mode interference principle is introduced.Based on the characteristics of the sensor,the feasibility of the sensor can be analyzed as the basis of this research,and the concentration sensing experiment of glucose is realized.2.Describe the difference between the single mode fiber and the multimode fiber,the principle of the coupling mode theory and the multimode interference are expounded,and the evanescent wave sensing principle of the optical fiber surface is further elaborated.The calculation formula of the penetration depth of the resonant wavelength and evanescent wave of the multimode fiber is derived by theoretical deduction,and the feasibility of the corrosion type SMS fiber sensor is analyzed according to the formula,which provides the corresponding theoretical basis for the subsequent research and analysis of this paper.3.Use simulation software beamprop is used to simulate the distribution of the transmitted light field in the single-mode multimode single mode optical fiber.It is analyzed that when the incident wavelength,the core size and the length of the multimode fiber change,the transmission field of the multimode fiber will be changed and the transmission spectrum will be affected.It will provide reference for the design of the experiment.4.Design and fabricate 2 kinds of optical fiber sensors with corrosion type SMS,and test the refractive index sensitivity of the structure fiber with different concentration of glucose refractive index,and the sensitivity of the refractive index is 91.61nm/RIU and 27.297nm/RIU respectively.Then based on immobilized enzyme technology,the glucose sensing experiment was carried out after the sensor was immobilized.The sensitivity of the sensor was 2.7pm/(mg/ml)and 2.8pm/(mg/ml)respectively.The specificity test of the sensor was carried out,and the feasibility of the sensor was verified.