PROBLEM TO BE SOLVED: To compensate an optical loss characteristic of an optical fiber to be measured without causing extra power loss in measurement of optical fiber strain.;SOLUTION: An optical fiber strain measurement device comprises: a light source unit that generates probe light; a first wavelength separation filter that separates and extracts a Stokes component of backward Brillouin scattering light from backward scattering light generated in an optical fiber to be measured by probe light; a self-delay heterodyne interferometer that has a polarization controller controlling polarization of the Stokes component, and that detects change of a frequency shift quantity of the Stokes component as a phase difference; and a polarization control unit that has a second wavelength separation filter which separates and extracts anti-Stokes component from a remaining component of the first wavelength separation filter. The polarization control unit acquires a loss characteristic from the optical fiber to be measured as a reference signal from the anti-Stokes component, subtracts the reference signal from the observed signal obtained by a self-delay heterodyne interferometer, and controls the polarization controller in such a manner that a detection level of the observed signal after subtraction is maximized.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2019,JPO&INPIT
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