Research On The Fabricating And Application Of Optical Fiber Micro-structure Sensors

Optical fiber micro-structure sensors have attracted much attention in the field of optical fiber sensing.It has many advantages,such as simple structure,easy preparation,multi-parameter sensing and high sensitivity with potential application value in physics,biochemistry and other sensing fields.The work of this thesis is to study the theory,fabrication of novel micro structural sensors,and research on their performance in physical quantities experiments to testify their prospects in different applications.The specific contents of the paper are as follows:1.We described the development background and application of optical fiber micro-structure sensor and introduce several typical microstructure sensors about manufacturing,principles and applications.2.A fiber sensor based on s-bend fiber and spherical-shape structure for refractive index and temperature testing is fabricated.For analysis the working principle of this sensor,the energy simulation of the fiber core when light propagate through the spherical-structure is performed by Rsoft software,and the spatial spectrum of the transmission spectrum is analyzed by fast Fourier transform.In the temperature testing,we focus on the high temperature section of the study.3.A novel sensing structure for etching long-period gratings on a spherical structure is proposed.The transmission spectra are analyzed and compared with the transmission spectra of conventional long-period fiber gratings.We are focusing on the analysis of the sensor's working principle.The experimental results show that the sensor has high curvature sensitivity,and also can simultaneously demodulate wavelength and intensity demodulation.Finally,explore and discuss the reasons for the high curvature sensitivity of the sensor.4.We also proposed a sensor by etching long-period grating on peanut structure for micro displacement and curvature simultaneous measurement.Two dips of sensor's spectrum are selected in order to monitor the wavelength shift.After the micro-displacement and temperature experiment,sensitivity matrix is introduced to calculate the variations of micro-displacement and temperature by substuting the sensitivities into the matrix,thus simultaneous measurement can be achieved.