Research On Biconical Mach-Zehnder Interference Based On Photonic Crystal Fiber And Its Sensing Characteristics

With the development of society and the advancement of science and technology,fiber optic sensors based on Mach-Zehnder Interference have played a huge role in many fields,such as military,defense,aerospace etc.Due to its advantages of compact structure,corrosion resistance,electromagnetic interference resistance,electrical insulation,and high sensitivity,it can replace manual work on many special occasions and has become a hot spot for researchers.Photonic crystal fiber is a new type of special optical fiber,which has a composition structure and many excellent characteristics that are different from ordinary optical fiber.The sensor,after the photonic crystal fiber is tapered,can change the internal composition structure and sensing characteristics of the fiber,and exhibit better characteristics and improve its sensitivity in fiber sensing.Therefore,this paper designs a biconical Mach-Zehnder interferometer based on photonic crystal fiber and combines simulation and experiment to study its sensing characteristics.The specific research content is as follows:In this paper,a double-cone Mach-Zehnder interferometer based on photonic crystal fiber is designed.It is a kind of photonic crystal fiber that is fused at two ends to two standard singlemode fibers,and the two welding points are tapered Fiber optic sensor made afterwards.Using FDTD Solutions optical simulation software to model the physical structure of the sensor,the influence of parameters such as the cone diameter,length and photonic crystal fiber length on the sensor performance was studied,and the optimized sensor structure was obtained.Through simulation,the refractive index sensing characteristics and temperature sensing characteristics of the biconical Mach-Zehnder interferometer based on photonic crystal fiber are investigated,and the theoretical sensitivity is 95.906nm/RIU,and the sensor is not sensitive to temperature and performance less affected by temperature crosstalk.The manufacturing process of the biconical Mach-Zehnder interferometer based on photonic crystal fiber was studied.Two Mach-Zehnder interferometers with different interference arm lengths were fabricated respectively,and an experimental test system was created to test the sensor performance,The sensor was tested in different concentrations of glycerin solution and the sensor characteristics were discussed.The sensitivity of the sensors with PCF lengths of 2.8 ? and 4 ? was measured to be 88.5nm/RIU and 121.95nm/RIU,Comparative analysis shows that the longer the PCF length,the higher the sensor sensitivity and the better the performance.