Research On Intensity Modulated Acceleration Sensing And Detecting Technology Based On Eccentric Core Fiber

Optical fiber acceleration sensor with small volume,anti-interference,light weight,and other advantages,have a wide range of applications in the aerospace,building Bridges,biomedical and other fields.Eccentric-core optical fiber as a kind of special fiber,because of its unique structure,can be more sensitive to environmental changes,also received wide attention and research.Based on the eccentric-core fiber sensing technology and acceleration detection technology,this paper designs a new type of optical fiber acceleration sensor system.This paper introduces the research progress of fiber optic sensing technology,core fiber optic fiber technology and acceleration sensing technology,and the significance of research on fiber acceleration sensing technology.The transmission optical theory of light and the principle of transmitting optical fiber are described.Using conformal mapping method of electromagnetic field,deduced the characteristic equation of the partial core optical fiber and the propagation constant,established a theoretical calculation model of partial core optical fiber,analyzed the partial core optical fiber transmission characteristics and bending properties of.Rsoft software and BPM method are used to simulate the characteristics and bending characteristics of the core fiber,and the relationship between the core distance,bending radius and bending loss of the partial core fiber is obtained.Thorough analysis is studied based on the quality of block-spring acceleration system damping ratio and frequency ratio and the relationship between the system parameters,such as natural frequency,have the best damping ratio 0.6-0.7 range,and gives its amplitude-frequency characteristic and phase frequency characteristic curve.With dual optical path differential detecting method,a eccentric-core optical fiber longitudinal acceleration sensor system based on the triangle cantilever beam-quality block structure is designed.Including the acceleration sensor unit,preamplifier circuit and filter circuit were also designed.Calculating and simulating the system model,thispaper got the system's inherent frequency of 200 Hz.The models and parameters of important optical elements such as light source,fiber coupler and photoelectric detector are set up.Using Labview virtual software and PC data acquisition card,to monitoring,collecting and processing the data.The experiment verifies that the system and the theoretical expectation are basically consistent and feasible,which lays a foundation for the further realization of the application of the acceleration sensor of the core fiber.In this paper,a transverse acceleration sensor model of double spring-mass block structure is designed,and the longitudinal model and transverse model can be used to measure the three-dimensional acceleration.