Research On The Application Of Optical Fiber Sensor For Human Health Parameters Detection

With the improvement of quality of life,people pay more attention to their own health problems.The detection of human health parameters is the basis for the discovery,control and treatment of diseases,and it reflects whether the body is healthy.The measurement of the urea concentration in the human body represents the health of the body's kidneys,and temperature is one of the vital signs and monitoring parameter in medicine.Therefore,online monitoring of urea concentration and temperature is quite critical.As a new type of sensing technology,optical fiber sensors possess the characteristics of light weight,good biocompatibility,anti-electromagnetic interference,and have irreplaceable advantages in biomedicine.For the detection of human health parameters,based on the optical fiber sensing technology,photothermal effects of biomolecules is combined with nano-functional materials to enhance the interaction with the surrounding environment to achieve high-sensitivity detection of external parameters.By designing different types of optical fiber structures,the concentration measurement of urea,a characteristic substance in human health parameters,is achieved,and it can become the basis of intelligent medical health monitoring.The main research contents of this paper are as follows:1.A urea concentration sensor based on functionalized long period fiber grating is proposed.The long period fiber grating was functionalized by graphene oxide(GO),and then the urease was immobilized on the surface of the optical fiber to achieve specific detection of urea.The results are as follows:the urea concentration sensitivity of the sensor can achieve-46 pm/mM ranging from 1 mM to 100 mM,and the detection limit is 0.43 mM.The temperature sensitivity of the sensor is 63 pm/?in the range of 25-50?.The proposed sensor has good prospects in biomedicine.2.A Sagnac loop optical fiber sensor based on the photothermal effect of urea is proposed.The core-core fiber coated with GO is used as the sensing area of the sensor.When the sample is irradiated by a pump laser beam,the solution produces a photothermal effect(PTE)that causes shifts in the resonance wavelengths.The urea concentration sensitivity of the sensor based on the PTE of urea can reach-6.2pm/mM in the range of 10-400 mM,and the detection limit is 3.2 mM,which is 13times higher than the bare fiber used for direct measurement.The sample detection method of photothermal effect provides new ideas for biomolecules research.3.A high-sensitivity optical microfiber temperature sensor based on liquid cladding is proposed.The sensor is made by arc discharge and flame-brushing technology,and is encapsulated in a capillary tube and covered with deionized water.Compared with silica material,the sensor based on liquid encapsulated has a larger thermal-optical coefficient.The temperature sensitivity of the liquid-encapsulated microfiber sensor can reach-415 pm/?ranging from 30-50?,which is 7~+times the sensitivity of bare optical fiber.This method not only effectively improves the sensitivity of the sensor,but also the water cladding can protect the ultra-fine fiber from damage,which has considerable application value in biomedical diagnosis and chemical research.