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Time Delay Measurement in Optical Fibers Based on Phase Detection

We developed an efficient and accurate fiber transfer delay measurement system. The main principle is to convert the fiber transfer delay in time domain into the phase detection, and eliminating the ambiguity by frequency scanning, followed with data process to get the result. This system has a resolution of picosecond, with an accuracy of 4 picosecond and a dynamic range of 40km. We also presented an uncertainty analysis and the implementation required to achieve results of the highest accuracy.