Study On Theory And Application Technology Of Distributed Optic Fiber Temperature Sensor

Distributed optic fiber temperature sensor is a new kind of technique studied in these years. In a sense, it can be called as Distributed Optic Fiber Raman Photon Sensor. Utilizing optic fiber back spontaneity dispersion phenomenon and optic time domain (OTDR) theory, temperature data at any point can be obtained; the position of every measured point can also be confirmed. So it is possible to synchronously monitor space-distributing state of measured point and variational temperature information along time. Owing to the characteristics of insulation, light quality, good flexibility, convenient installation, defending burning and exploding, enduring high voltage and strong electromagnetic field, optic fiber is fit for deleterious circumstance. The cost will be reduced, because the distributed measurement is realized with the single optic fiber replacing a lot of drop sensors. Distributed optic fiber temperature sensor system can resolve distributing measurement problems in underground, tunnel and transmitting oil pipeline, and so has great economy advantage and social benefit.This dissertation is mainly devoted to theoretical and experimental investigations on distributed anti-Stokes ratio thermometry sensing for monitoring temperature in complicated structure.It has been explained why the relation between Stokes light and temperature is different in theory and practice. This is the basis for understanding distributed anti-Stokes ratio thermometry objectively.A technique, based on maximizing signal to noise ratio (SNR) of the system, has been proposed. This method includes the determination of optimum wavelength of the laser and avalanche gain of the avalanche photodiode (APD).