Development Of The Fully Distributed Fiber Optic Sensor System

Optical fibers recently have become more important elements in communication and sensor systems due to their high efficiency of transport and large bandwidth. These properties have made optical fiber sensor increasingly more important than the traditional sensors. Especially, people pay more attention to the fully distributed optical fiber sensor for it's large scale, high resolution and less error.In this dissertation, the thermodynamics equilibrium condition, modal and arithmetic to the fully distributed optical fiber sensor on base of Raman and Rayleigh optical back scattering reflectometry are studied.The fully distributed optical fiber sensor system is studied by theory and emulational methods. The contents are organized as follows:Chapter 1. an over view of the research background is introduced, and the advantages of the fully distributed optical fiber sensor on base of the OFDR (optical frequency domain backscattering reflectometry) are presented.Chapter 2. spontaneous Raman scattering and the Raman scattering power of one molecule are analyzed.Chapter 3. the Bose-Einstein distribution and the thermodynamics equilibrium condition which are obeyed by the photons during spontaneous Raman scattering in the fiber are developed. The occupation probability ( s, AS) of stokes photon and anti-stokes photons and temperature (T) can be regarded as the function of the position along the fiber axis.Chapter 4. the fully distributed temperature multimode step-index fiber optic sensor based on spontaneous Raman optical frequency-domain reflectometry is developed.Chapter 5, the fully distributed temperature multimode graded-index fiber optic sensor based on spontaneous Raman optical frequency-domain reflectometry is further developed by two methods.Chapter 6, the fully distributed temperature single mode step-index fiber optic sensor based on spontaneous Raman optical frequency-domain reflectometry is developed.Chapter 7. the theoretical model of Rayleigh optical frequency domain reflectometry is presented, and the fully distributed microbending loss optical fiber sensor on base of this model is studied.Chapter 8. the fully distributed optical fiber sensor system on base of Raman and Rayleigh optical frequency-domain reflectometry to measure microbend and temperature simultaneously is developed.