Research On High Sensitivity Optical Fiber Pressure Sensor

As a sensor, the optical fiber sensor is so important. It is widely used in signal detection and sensing field. In all kinds of high sensitive optical fiber sensor, the method of Fabry-Perot has the characteristics of simple structure, short cavity length, and high precision. So it has the highest degree in its practical application. To improve the sensor sensitivity and keep the advantages of small volume, diaphragm pressure sensors have become the focus in the recent frontier, which are based on the extrinsic Fabry-Perot interference. At this stage, the etching method of forming the hollow cavity and the chemical synthesis method of making the films in the extrinsic type optical fiber pressure sensor have been able to realize successfully the optical fiber pressure sensor production and application. Based on the above, this paper completes the preparation and optimization of the sensing film by regarding the capillary glass tube as a cavity and using thermal deposition method. What’s more, the article explores the low loss of submicron membrane transfer technology. The following research work has been carried out:First of all, the development of fiber optic sensor is introduced, and the sensing characteristics of fiber optic diaphragm pressure sensor and its application in sensing field are described.Secondly, we research the sensing mechanism of diaphragm type pressure sensor and analyze the interference theory in the extrinsic diaphragm type optical fiber pressure sensor.Thirdly, the article studies systematically the diaphragm’s deformation principle and frequency response characteristics in the preparation process of the sensors. Besides, by analyzing diaphragm’s parameters, such as material, shape, size, thickness, on the influence of the sensor performance, we managed to explore the method for low loss transfer for evaporation of diaphragm. As a result, we put forward a new cavity structure which is based on the new type metal film and finish the preparation of pressure sensing head.Finally, we prepare the sensors by using capillary glass tube, single mode fiber, and metal film, complete a simple filter amplifier circuit design and production and set up a test system for the pressure sensor. Besides, we measure and analyze the sensing characteristics of the pressure sensor which is put forward in this article so that we get the optical fiber pressure sensor which has a higher sensitivity.