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Study Of Mach-Zehnder Optical Fiber Interferometric Composed Of The Instrument Optical Fiber Sensor

Posted on:2019-07-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y H HuFull Text:PDF
GTID:2428330545959831Subject:Optoelectronic devices
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With the rapid development of optical fiber technology,optical fiber sensing technology has developed rapidly in 1970 s.As a new type of sensing technology,fiber sensing technology has been widely used in the optoelectronic technology industry.A variety of physical quantities can be measured with optical fiber sensor,such as temperature,refractive index,stress,pressure and so on.Compared with the traditional electric sensor,optical fiber sensors have the advantages of anti electromagnetic interference,low loss and high precision.In this paper,four kinds of optical fiber sensors with different Mach-Zehnder interferometer(MZI)structures are put forward,and the structure,sensing mechanism and characteristics of the four sensors are analyzed theoretically and experimentally,the main contents include:1.To realize high-precision temperature and stress measurement,a highly sensitive optical fiber sensor is designed and fabricated by using femtosecond laser micromachining technology.The operation mechanisms of the temperature and stress measurement by the fiber micro-cavity structure are theoretical analyzed.The sensing experiments of the ambient temperature and the axial stress measure are finished.The experimental results show that the temperature sensitivity is 54.29 pm/? and the stress sensitivity is 1.1 pm/??.2.To realize high-precision temperature and stress measure,a MZI is fabricated by using wavelength 800 nm femtosecond laser and fused fiber taper cone machine,and temperature and stress are measured simultaneously.The operation mechanisms of temperature and stress measurement by Mach–Zehnder interference are theoretical analyzed.The sensing experiments of the ambient temperature and the axial stress measure are finished.The experimental results show that the dip1 sensitivities are 40.4 pm/? and 0.32 pm/??,and the dip2 sensitivities are 52.0 pm/? and 0.38 pm/??.3.Taking use of mulit-core fiber(MCF)and optical fiber offset fusion technology,an all fiber MZI is made for simultaneous measurement of temperature and refractive index.The experiment results show that the peak wavelength of transmission spectrum of the sensor shift linearly with the change of temperature,and the temperature sensitivity are 54.238 pm/?.While the peak intensity of transmission spectrum of the sensor is no sensitive to the temperature change.The peak intensity of transmission spectrum of the sensor shift linearly with the change of refractive index,and the refractive index sensitivity is 10.704 dB/RIU.While the peak wavelength of transmission spectrum of the sensor is no sensitive to the refractive index change.Due to using of wavelength modulation and intensity modulation methods for temperature and refractive index measurement,respectively,the sensor can overcome the cross sensitive problem of two-parameter measuring simultaneously.4.Taking use of plastic clad fiber(PCF)and fiber optic fusion technique,an all fiber MZI is fabricated for simultaneous measurement of temperature and refractive index.The principle of simultaneous measurement of temperature and refractive index by the sensor was theoretically analyzed.The experimental results showed that the sensitivity of the temperature and refractive index could be obtained by the two resonant peaks(dip1 and dip2)of the transmission spectrum.The sensitivity of the temperature and refractive index of the first resonant peaks(dip1)were 12.0 pm/ and 39.18nm/RI,and the sensitivity of the temperature and refractive index of the second resonant peaks(dip2)were 13.3 pm/ and 52.56 nm/RI.The four types of designed optical fiber sensors in this paper have the advantages of easy fabrication,high sensitivity,simple structure and so on.It has a very high application prospect.
Keywords/Search Tags:Mach-Zehnder fiber interferometer, optical fiber sensor, micro fabrication technology of femtosecond laser, fiber fusion technology, mulit-core fiber, plastic clad fiber
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