Phase-OTDR based on space difference of Rayleigh backscattering

Phase-OTDR based on space difference of Rayleigh backscattering is proposed. The Rayleigh backscattering from different segments of the test fiber interfere by adjusting the path difference of the imbalance Michelson interferometer. According to the resemble polarization and intensity of two path light, amplitude, frequency of the acoustic signal at the different locations along the sensing fiber can be simultaneously demodulated, and we realize the acoustic signal demodulation of different intensities..