HIGH-RESOLUTION DISTRIBUTED TEMPERATURE SENSING WITH THE MULTIPHOTON-TIMING TECHNIQUE

We report on a multiphoton-timing distributed temperature sensor (DTS) based on the concept of distributed anti-Stokes Raman thermometry. Th e sensor combines the advantage of very high spatial resolution (40 cm ) with moderate measurement times. In 5 min it is possible to determin e the temperature of as many as 4000 points along an optical fiber wit h an accuracy Delta T < 2 degrees C. The new feature of the DTS system is the combination of a fast single-photon avalanche diode with speci ally designed real-time signal-processing electronics. We discuss vari ous parameters that affect the operation of analog and photon-timing D TS systems. Particular emphasis is put on the consequences of the noni deal behavior of sensor components and the corresponding correction pr ocedures.