Fiber Micro Fabry - Perot And Bragg Grating Accelerometer

Since the advent of fiber sensors,due to the advantages of its high reliability,corrosion resistance,free from electromagnetic interfernce,multiplexing capability,low transmission loss,and long distance that traditional electrical sensor can not match,obtaining much concern of researchers,and in recent decades it became the fastest-growing fiber-optic passive component. In many kinds of fiber-optic sensors, used to measure the acceleration sensor to meet major national needs with potential applications, such as earthquake monitoring, safety monitoring key facilities, power industry and oil exploration fields.This paper studies two important acceleration sensor: one is an accelerometor based on closed micro-optical F-P sensor, the other one is a long-distance FBG acceleration system based on Raman amplification. The former methods for meeting people device of miniaturization, lightweight, high temperature capability, explosive and other harsh environments such as the urgent demands of work across F-P sensor , while the latter have displayed great advantages in the long distance and reuse. The concrete work done as follows:I. Briefly introduced the measuring principle and main categories of acceleration sensor,analyzed working principle,advantages and disadvantages of the current typical fiber-optic acceleration sensors,proposed main contents of this article, and key research objectives,innovation, analyzed the sensing principles of fiber FBG sensors and fiber F-P sensors, and briefly describes two methods of signal processing.II. Simulated specific parameters cantilever with finite element analysis (ANSYS), analyzed its dynamic pattern and static stress, calculated the natural frequency of the cantilever, 1g acceleration effect of strain and horizontal cross-talk, and the principal stress and Von Mises stress under 100g accelerationon the cantilever.III. Overviewed the 157nm excimer laser micro-processing technology and the technology based production closed micro-fiber Fabry-Perot sensor technology and processes. Studied the acceleration response characteristics of closed micro-optical F-P sensor at room temperature,. Found that the new structure of opticl fiber F-P sensor has great resolution, FFT signal to noise ratio is 30dB, the resolution ratio is 1.13mg/Hz1/2. Processing the signal by MUSIC algorithm, signal to noise ratio can be increased to 75dB, the resolution ratio is 3.56 x 10-2μg/Hz1/2. Insensitive to temperature and its features help it applies to highways, bridges, dams and other large structural health monitoring.Ⅳ. Designed a ring laser long distance Fiber Bragg Grating (FBG)acceleration sensor system based on Raman amplification, starting from the principle of Raman scattering, described the principle of the ring laser, and the performance of the system was experimentally studied, the MUSIC algorithm is also used to improve the system SNR.