Study On Dual-Fiber Grating Sensor

In this work, a simple optical fiber grating sensor is proposed and demonstrated. It can find applications in special environments with lower cost and accuracy, and also it will expend the application of fiber grating sensor.First of all, we analyze the theory of the dual-fiber Bragg gating sensors. Then we design a stress sensor based on double-chirped fiber grating and a temperature sensor based on double polarization maintaining fiber grating.1) This part consists of three points, namely, the theories of temperature sensor and strain sensor, the solution of temperature and strain cross-sensitivity, and the progress of packaging technology.2) According to the coupled mode theory, we derive the characters of chirped grating and polarization maintaining fiber grating. Simulations are carried out.3) A double-chirped fiber grating stress sensor is proposed in this part. A new traffic monitoring system is constructed based on the combination of the new sensor and single chip. In the proposed scheme, the analog signal is first converted to the digital signal through the single chip interface technology, and then we develop a MPU programming to process acquired data. Finally, the system successfully identifies the axle by detecting voltage changes, and determines the vehicle mode through single chip sampling operations. The results shows that the traffic monitoring system could identify the vehicle mode correctly, accomplish traffic flow monitoring.4) A temperature sensor is proposed based on polarization maintaining fiber grating. By using this sensor and optical maser, the temperature sense could be accomplished. This paper verified the feasibility of the sensor through numerical calculation and simulation.