Research On Interferometric Optical Fiber Sensing Characteristics Of GO Coated Photonic Crystal Fiber

In recent years,optical fiber sensing technology has been widely studied due to its advantages such as flexible design,anti-electromagnetic interference,corrosion resistance,and easy integration.It plays a very important role in many fields such as biochemistry,food safety,environmental monitoring,and communications.Photonic crystal fiber(PCF)can obtain new characteristics by combining with sensitive substances,which has become an important research direction of optical fiber sensors.Graphene oxide(GO)has excellent hydrophilic properties and can be used as a humidity-sensitive material to detect humidity and improve the sensitivity of the sensor.In this thesis,three Mach-Zender interferometers(MZI)are designed and manufactured by PCF based on the principle of interference.The temperature,humidity and glucose concentration sensing characteristics of GO-coated fiber structures have been studied respectively.The main research contents include:1.A temperature and humidity sensor based on PCF coated with GO cascaded with two spherical structures is designed.The fusion method is introduced,and the energy distribution of the structure is solved by Rsoft simulation software.The spherical structure is used as a coupler of the sensor,and the intermediate PCF is used as the sensing region of the sensor.The optimal length is obtained by exploring the relationship between the length of PCF and the spatial spectrum.The sensor surface is coated with optical driven deposition(ODD)for humidity sensitivity.The sensor is used for temperature and humidity experiments,and the drift of the spectrum is observed.Experimental results show that the temperature sensitivities of the two interference valleys are 0.605nm/? and 0.795nm/?,respectively;the humidity sensitivities are 0.128nm/% RH and 0.159 nm/% RH,respectively.The manufactured sensor has a good linear relationship for the detection of temperature and humidity characteristics.2.A temperature and humidity sensor based on PCF coated with GO and filled with alcohol cascaded with two spherical structures is designed.The fusion method is introduced,and the energy distribution of the structure is solved by Rsoft simulation software.The optimal length is obtained by exploring the relationship between the length of PCF and the spatial spectrum.The PCF is filled with alcohol by the reduced pressure injection method,and the sensor surface is coated with GO to achieve sensitivity enhancement.The sensor is used for temperature and humidity experiments,and the drift of the spectrum is observed.Experimental results show that the temperature sensitivities of the three interference valleys are 0.193nm/?,0.070nm/? and 0.073nm/?,respectively;the humidity sensitivities are 0.109 nm/%RH,0.067 nm/% RH and 0.108 nm/% RH,respectively.The manufactured sensor has a good linear relationship for the detection of temperature and humidity characteristics,and can simultaneously measure dual-parameters.3.A PCF sensor based on GO composite film modification to simultaneously measure humidity,temperature,and glucose concentration is designed.The composite film combines GO with polyvinyl alcohol(PVA)and glucose oxidase(GOD),respectively,and studies the sensitivity to humidity and glucose concentration.Experimental results show that the temperature sensitivities of the three interference valleys are 0.059nm/?,0.121nm/? and 0.047nm/?,respectively;the humidity sensitivities are 0.109 nm/% RH,0.067 nm/% RH and 0.108 nm/% RH,respectively;the glucose concentration sensitivities are 0.028nm/(g/L),0.047 nm/% RH and 0.031nm/% RH,respectively.The structure can detect multiple physical parameters and has a simple structure,which can be applied to fields such as biomedicine and environmental monitoring.