Based On The Fiber Ring Laser With Fbg Dynamic Strain Sensing System

In the practical engineering fields, vibration measurement issues related to the safety of large engineering structures, whereas the electromagnetic acceleration sensors which are commonly used now are difficult to meet the requirements, such as multiplexing and free from electromagnetic interference. Fiber Bragg Grating (FBG) sensors not only have the traditional function of the electromagnetic type sensor but also have high sensitivity, easy to multiplex, free from electromagnetic interference, corrosion resistance and other characteristics, so the research on FBG vibration technology is of great significance.A vibration measurement program is presented in this paper and analyzed from theoretical and experimental. The main work can be summarized as follows:1. The characteristics and classification of fiber optic sensors, as well as domestic and international fiber optic sensor research and development status is described briefly. The basic characteristics of FBG, sensing principles, and common demodulation methods are overviewed, and the advantages and disadvantages of demodulation methods are analyzed in detail. The applications of vibrate sensors and FBG vibrate sensor status is summarized.2. A FBG sensor system with F-P etalon demodulation and Music Algorithm for dynamic strain measurement is designed. The laser design principles are analyzed from the pump wavelength, the resonant cavity and gain medium, ultimately a laser which is suitable for system is designed and the corresponding demodulation system is also designed. A calibrate FBG which is used to calibrate the dynamic strain applied to the FBG was mounted on the opposite on the cantilever beam directly underneath the sensing FBG. In order to improve the dynamic strain resolution, the Music algorithm is used to analyze the system signal.3. A FBG sensor system with M-Z interferometer demodulation and Eigenvector spectrum analysis method for dynamic strain measurement is designed. The interference demodulation method is used, and the light source is designed which is depended on the requirements of interferometer demodulation instrument. The performance of fiber ring laser is researched from stability, side-mode suppression ratio, line-width and frequency drift. The reference FBG is used to eliminate the slow drift of the M-Z interferometer and calibrate the dynamic strain applied to the FBG. Due to the excellent white-noise suppression capability of Eigenvector method used, the system dynamic strain resolution is greatly improved.