Research On Optical Fiber Mach-Zehnder Interference Sensor Based On An Inner Cavity

Fiber Machzand interference(MZI)sensor based on long cavity is designed and fabricated by femtosecond laser micromachining,arc discharge and HF acid etching.Based on the whole process from the determination of research direction to the publication of research results,the fabrication process,theoretical basis and advantages and disadvantages of fiber Mach-Zehnder interference sensor based on long cavity are discussed in detail,which provides a theoretical basis for the practical application of this type of fiber sensor.The details are as follows:1、The significance and development of optical fiber sensing are introduced.Then the classification and characteristics of optical fiber sensors are summarized,and the principle and research status of optical fiber sensors based on M-Z interference are introduced.Finally,the advantages and applications of optical fiber sensing are introduced.2、Discuss the analysis of the development of femtosecond laser micro processing technology as well as the role in the material as a result,and then summarized by femtosecond laser micro processing technology of the preparation of fiber microstructure,find out the deficiency of the existing technology,a preliminary determine the research direction of this article,finally the structure of the preliminary design is verified by experiment,analyzes the structure,preparation,the main points of the research direction for the reasonable correction.3、An optical fiber M-Z interferometer based on a long spindle cavity is proposed.The structure made in a single mode fiber can accurately measure the high temperature(1000℃),and the sensitivity is 23.88 PM /℃ in the temperature range of 25-400℃ and33.5pm/℃ in the temperature range of 400-1000℃.The refractive index can be measured by fabricating the structure in multi-mode fiber,and the refractive index sensitivity is47.87nm/RIU.4、In order to further explore the application of optical fiber M-Z interferometer based on air cavity in optical fiber sensing,an optical fiber pressure sensor with open channel is designed and manufactured.The device is based on a conical gas chamber,and a micro channel connected to the external environment is generated by HF acid etching method,achieving accurate and stable measurement of gas pressure.The structure has very low temperature cross crosstalk(2.58 kPa/℃)and high pressure sensitivity(3351pm/MPa).The three types of optical fiber sensors proposed in this paper can realize the accurate sensing measurement of high temperature,refractive index and air pressure respectively.Different sensor structures have unique advantages,stable performance,simple production,low production cost and so on,making it possible to practical application in engineering...