The Experimental Fabrication And Sensing Characteristics Research Of Microstructure Fiber Optic Sensors

Microstructure fiber has unique structure characteristics,which plays an important role in the field of fiber technology.Compared to traditional fiber,this type of fiber has a lot of new sensing characteristics.In order to meet the needs of modern industry,people improve this type of fiber continuously to make it own diverse structure and excellent transmission characteristics,which make the fiber sensors based on microstructure optical fiber exhibit outstanding performance.Nowadays,it has already applied to all areas of society because of unique advantages.On this basis,with the continuous study of the sensor principle and production technology by researchers,there have been a lot of new microstructure optical fiber sensors appear.Besides,they have gradually realized the commercialization of the technology and applications,which make the positive influences on our lives.However,in industry,aerospace and ship and other extreme environments,owing to the existence of high temperature and pressure,strong radiation and electromagnetic interference and other factors,many traditional sensors can't access physical information effectively,which requires us to develop more new sensors to adapt this type of environment.The main work of this paper is that we experimentally fabricate several kinds of new optical fiber sensors.It is divided into the following parts.(1)The basic knowledge of FBG sensors and the experimental methods of FBG preparation are introduced and the experimental platform to engrave FBG is built.Than we fabricate the FBG on microfiber and single mode fiber and study its temperature and strain sensing properties.The experiment results show the temperature sensitivity of the FBG in microfiber is close to that in the single mode fiber,and the strain sensitivity can be effectively improved by reducing the diameter of the fiber.(2)By using femtosecond laser assisted selectively infiltration technique and fiber splicing technique,we design a microstructure optical fiber sensor of filling index matching liquid.We apply the device to strain and temperature sensing measurements.Finally,the experiment results show that this sensor filled with refractive index matching liquid has high strain sensitivity and low temperature sensitivity,so it can meet the needs of some high sensitivity strain testing.(3)By utilizing manual coating method and fiber splicing technique,we infiltrate one side air holes of the dual-core microstructure optical fiber with water and design such filling device.We apply the device to strain and temperature sensing measurements.Finally,the experiment results show that this sensor filled water has high temperature sensitivity and low strain sensitivity.The applied strain has little effect on the water in the air holes,so it can't improve its strain sensitivity.(4)By applying fiber splicing technique,we design the optical fiber liquid level sensor based on the silica tube.In order to study the sensing characteristics of the sensor,it is applied to the experimental measurement of water level and temperature sensing.The experiment results show the liquid level sensitivity of this sensor is high and the temperature sensitivity is low.In addition,it is proved that this sensor can work in a wide refractive index range(1.300-1.700),which covers the most commonly used liquid.