Optimal Design Of A Distributed Optical Fiber Temperature Sensor System

The temperature sensor has been developed for many years, but the previous devices based on electrical signals, easily to be influenced by electromagnetic interference and intolerance of high temperature and high pressure, in constract, the distributed optical fiber temperature sensor system’s medium to get and transfer the information is optical fiber, it can be insulated to electrical. The quality of the optical fiber is slight, and has a good corrosion resisting property, it’s easy to be built and maintained. This system also has an advantage that it can make a long distance real-time online temperature monitoring, so that the distributed optical fiber temperature sensing system breaks the limitation of the traditional sensors. Since the emergence of this system, it has been widespread concern in various scientific research institutions and companies, after decades of years’ research, it has been widely used in the coal mine safety production, oil transportation, and other special places. It has opened up a new research direction in the field of temperature monitoring, and has a good development prospect.Firstly this paper elaborated the development of the distributed optical fiber temperature sensor system, noted the main entry point for our country’s research, and then, introduced the principle of Raman scattering theory and Optical Time Domain Reflection technology, analysed the calibration method of temperature and the method to demodulate Raman scattering.This paper, discussed the performance index of this system, then designed the optical signal generating module, the photoelectric detection circuit, and the signal acquisition unit. Aiming at the laser, this paper designed the temperature control circuit in order to ensure power stability, effectively prevented the occurrence of nonlinear distortion. For the stability of this system, the spatial resolution, the temperature resolution, we made a detail analyse to these parameters. In the fifth chapter made detailed analysis of wavelet analysis, introduced the principle and transformation of wavelet signal processing, then puts forward how to choose the parameters of wavelet analysis, used the chaeracters of the distributed optical fiber temperature sensor system to filter out noises of the nonstationary signals. In this paper, the MATLAB simulation on different parameters to simulate the wavelet denoising experiment. The results showed that the wavelet signal processing can effectively filter the noise in the signal, improved the system’s signal-noise ratio.