摘要 |
A measurement precision is improved and a measurement range is extended by efficiently suppressing a noise level of integrated unnecessary components from non-correlation positions. Measuring means 33 detects the Brillouin gain of a probe light output from a measurement-target optical fiber FUT while sweeping a frequency difference between the pump light and the probe light, and measures the distribution of strains of the measurement-target optical fiber FUT. An optical intensity modulator 4 performs intensity modulation on output light in synchronization with frequency modulation performed on a light source 1. Accordingly, the spectrum distribution with respect to the frequency of light from the light source 1 can be adjusted arbitrarily, and a noise spectrum shape generated at a position other than a correlation peak position and spreading over a frequency axis can be adjusted, and the peak frequency of a Lorentz spectrum generated at the correlation peak position can be measured precisely. Moreover, a measurement range dm can be extended.
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