Research On Optical Fiber Gas Sensing Performance Based Michelson Interferometric

With the development of industry,hydrogen sulfide?H₂S?,as one of the main exhaust gases in modern industry,brings a great threat to the life and health of professional workers.Therefore,it is extremely important to effectively monitor the hydrogen sulfide gas produced in industrial production in real time to ensure the safety of workers.As an important branch of modern information processing technology,sensor technology has been widely used in high-tech industries at home and abroad.Gas sensors,like human olfactory organs,can monitor the gas in the environment in real time and occupy an important position in the industrial field and national defense construction.When the traditional indirectly heated and resistive sensors work,the activity of the material needs to be catalyzed at a temperature of 100 degrees Celsius to make it work.Therefore,fiber-optic gas sensors work at room temperature is studied.Taking H₂S as the detection target,three different sensors are fabricated.In this paper,the main research work is as follows:?1?Multi-node interferometer was fabricated by thin core fiber?TCF?,and copper/graphene oxide?Cu/GO?composite material was coated on the surface of the thin core fiber to form a sensitive film with a thickness of 1.6?m.The sensor was tested for gas sensitivity,its sensitivity is 4.83 pm/ppm,response and recovery time are 32s,52s respectively,theoretically calculated that the limit of detection H₂S concentration of this sensor is 4.155 ppm.?2?Based on the structure of a multi-node interferometer,a Faraday rotation mirror?FRM?was used to make a Michelson interferometer?MI?based on a thin-core fiber,and the fiber Michelson interference principle was analyzed by the planar harmonic function.Aminated reduced graphene oxide?NH₂-rGO?was prepared what it was used graphene oxide?GO?by modification,which was analyzed by Raman spectroscopy and X-ray photoelectron spectroscopy ray photoelectron spectroscopy?XPS?analysis of the material showed that the material was successfully prepared;through scanning electron microscopy?SEM?observation,a thin film with a thickness of 500 nm was formed on the surface of the thin core fiber;through the concentration test of H₂S gas,its sensitivity is 21.3pm/ppm.?3?In order to avoid the influence of temperature on the sensor performance,a photonic crystal fiber?PCF?was used to make a MI.Titanium dioxide was prepared as a sol-gel material and was dipped on the surface of the photonic crystal fiber.Through the test of hydrogen sulfide gas concentration,the sensitivity is 10.43 pm/ppm;the sensor is less sensitive to temperature and can be ignored in the range of 20-65?.