Research On Sensing Characteristics And Wireless Transmission System Of Fiber Mach-Zehnder Interferometer

Fiber optic sensors have many excellent properties such as strong anti-interference ability,high sensitivity,flexibility and compactness,and have been widely studied in recent years.However,due to the limitation of the cable,the application of the wired sensor in a complex environment is limited,and the data of the optical fiber sensor is transmitted wirelessly,which can improve the application range of the optical fiber sensor.In this paper,a optical fiber Mach-Zehnder interferometer sensing structure is fabricated,and a set of systems for wireless transmission of data is produced.The research contents are as follows:Firstly,this paper introduces the research status and research progress of fiber optic Mach-Zehnder interferometer in recent years.The sensing principle of the fiber Mach-Zehnder interferometer is theoretically discussed and the basic principle of temperature sensing and refractive index sensing of the interferometer is described in detail.Then,the temperature sensing characteristics,refractive index sensing characteristics and displacement sensing characteristics of the coated optical fiber Mach-Zehnder interferometer were studied.the experimental results show that the structural temperature sensitivity can reach up to 4.224nm/°C.Insensitive to refractive index and responsive to displacement;the temperature sensing characteristics and refractive index sensing characteristics of uncoated curved fiber Mach-Zehnder interferometer were studied,the experimental results show that the structural temperature sensitivity can reach 0.046nm/°C,the refractive index sensitivity can reach 201.48nm/RIU.The experimental results of the sensing characteristics of the fiber interferometer with or without the coating layer are considered to have an effect on the measurement of the temperature and the measurement of the refractive index.Finally,using STM32F407,ESP8266 and Gizwits development platform,a system for data wireless transmission and display was created.The data can be uploaded to the cloud server through STM32F407 and ESP8266,and the data is displayed by the smartphone APP.Tests show that the system can achieve bidirectional transmission of data,providing the possibility for wireless data transmission of fiber optic interferometers.