Research On Capillary-based Fiber F-P Vibration Sensor

With the development of fiber-optic sensing technology in recent decades, optical fibersensor have been widely used in several tens of parameters sensing applications, and beenapplied in various fields. Fiber optic sensor for vibration detection is one of the hot researchfields. There are different kinds of fiber optic sensor for vibration detection. These includeintensity-based sensors (IBSs), Fabry-P′erot interferometers sensors and fiber Bragg-Gratings(FBG) sensors.Our research is supported by the National Natural Science Foundation of China:“BasicResearch for Key Technology of Fiber Earthquake Wave Monitoring in Major ProjectsDisaster Warning”, and investigation of the most frequently used vibration optical fibersensors and focuses on a capillary-based fiber FP vibration sensor. The main researchachievements are described as follows:(1) We fabricate a capillary-based fiber FP vibration sensor and test the capillary-basedfiber FP vibration sensor. The response of the sensor to the vibration frequency, vibrationamplitude and temperature are further studied. Through experimental demonstration, wehave found that the senor can detect the vibration frequency at0.1Hz accuracy and have adetection range from10Hz to60000Hz. This is the good experimental results to best of ourknowledge.(2) With a cascade of multiple sensors in different ways, we achieve quasi-distributedvibration sensing detection. The sensors can be cascaded in series and in parallel way,because the sensor is not only a transmission type sensor but also a reflective type sensor.The merits and demerits of different cascade systems are analyzed.(3) We package the capillary-based fiber FP vibration sensor so that the sensor can beapplied bad environment. The sensor package technology with plastic tube can overcome thevulnerability of the capillary so that the packaged sensor can be much easier applied inindustry environment.