High Fabrication Tolerance And Wide Detection Range Photonic Crystal Fiber Refractive Index Sensor

Refractive index is the inherent physical property of matter.The change of refractive index can reflect the change of physical and chemical properties of matter.Therefore,refractive index sensors are widely used in various fields.Optical fiber sensors occupy an increasingly important position in the field of sensors due to their unique advantages.Among many optical fiber sensors,photonic crystal fiber(PCF)has gradually emerged in the field of optical fiber sensing due to its flexible structural design and excellent light transmission characteristics.PCF sensors have been favored by more and more researchers in recent years.However,due to the complex structure of PCF and multiple air holes,it is difficult to achieve actual manufacturing.Therefore,it is of great significance for the practical application of PCF sensors to reduce the manufacturing difficulty of sensors,improve the manufacturing tolerance and broaden the application range of sensors through simulation experiments.In this paper,the actual sensing ability of single-mode PCF sensor is analyzed by refractive index sensing experiment,and its application in the field of refractive index sensing is verified.In order to improve the sensitivity of the PCF sensor,reduce the actual production difficulty of the sensor,and improve its production tolerance,a new structure of polished PCF refractive index sensor is designed.The sensor adopts side polishing design,and the analysis liquid is located outside the sensor,which can avoid the step of replacing the analysis liquid in the sensor and is convenient for practical use.The structural parameters of the sensor are analyzed and optimized by the full vector finite element method to achieve better sensing performance.After that,the tolerance limit of each parameter of the sensor is creatively analyzed,that is,how much the fabrication error can affect the sensing performance of the sensor.The numerical results show that the 5 % manufacturing error does not affect the performance of the sensor,which is undoubtedly of great significance to the practical application of the PCF sensor and provides a new research idea for the practical application of the PCF sensor.Broadening the detection range of PCF sensor can undoubtedly expand the application field of PCF sensor,so that it can meet the sensing needs of various fields.In order to meet the sensing needs of many fields,a polished PCF sensor with low refractive index detection capability is designed.The detection range is 1.20 ～ 1.34 RIU,and the detection width can reach 0.14 RIU.On this basis,a polished PCF sensor with ultra-wide detection range is designed and numerically analyzed.The detection range of the refractive index sensor is 1.04 ～ 1.42 RIU,and the detection width can reach 0.38 RIU.It is the widest among the currently known polished PCF sensors and can meet the sensing requirements in many fields.