Fiber Bragg Grating Sensing System Based On Time/Wavelength Division Multiplex

Sensing technology is one of the high and new technology’s focus of research in the world, and itis also the important symbol of the modern science and technology development. Sensor technology,computer technology and communication technology consist of the three information industry.When the fiber grating acts as sensing unit, its main advantage is that testing information forwavelength encoding has absolute measurement and good repeatability of the linear response of10-6~10-2four orders of magnitude.In addition, not only fiber grating sensor can be made of array, and it is theimportant components of realizing multi-point and quasi-distributed sensing measurement network, butalso it has advantage of low insertion loss, narrow reflection bandwidth, high temperature resistance,chemical stability and resistance to electromagnetic interference. Therefore, the fiber grating has beenregarded as a kind of ideal sensing material, all countries in the world have done lots of research in theseareas.Compared with the traditional sensing technology, the sensor based on optical fiber is mainly hasthe following several advantages:(1) high temperature resistance, resistance to electromagneticinterference, resistance to chemical corrosion (2) the light quality, compact structure,easy to multiplex (3)low cost and mass production (4) in the sensing point without electricity, can be used for long distancedistributed sensing.Therefore, the study of fiber grating sensing technology has very important significance.This paper puts forward a kind of fiber grating sensing system based on time/wavelength divisionmultiplex, the system consists of a driving circuit, a LED light source, the annular, the sensing grating, theMichelson interferometer, etc. The sensing system completes high frequency modulation by driving circuit;Its distributed sensing head makes of grating, and it can realize sense continuously in a wide rangeof space, The sensing system has practical value.Firstly, this paper introduces the background and development of the optical fiber grating sensor,and its application in medicine, civil engineering, petrochemical industry, power industry and other fields.Secondly, the paper describes the basic theory of the fiber Bragg grating sensor; Then the paperintroduces two types of the commonly used fiber Bragg grating sensors, namely the strain sensor and thetemperature sensor; Then the paper tells some detection methods of the optical fiber Bragg grating sensorsignals; Then this paper introduces the long period fiber grating sensor and other kinds of sensors.Finally, this paper describes the basic structure of the fiber Bragg grating sensor; After the papertells the design of the fiber Bragg grating sensor system based on time/wavelength division, includingdesign and analysis of the schematic diagram, performance of the system(selection of reflection wavelength,sensitivity,dynamic range and time interval), the system’s requirements and selection in the drive circuitand interference system and so on;Finally, this paper introduces the new fiber Bragg grating sensing systembased on the double loop aided Michelson interference in the first time,and then introduces the schematicdiagram of the sensing system.After the paper analyses the design scheme of the sensing system.