Yokogawa Electric Corporation

The University of Tokyo

Kwang Yong Song

Kazuo Hotate

Zuyuan He

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 meansdetects 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 modulatorperforms intensity modulation on output light in synchronization with frequency modulation performed on a light source. Accordingly, the spectrum distribution with respect to the frequency of light from the light sourcecan 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 dcan be extended.

Optical-fiber-characteristic measuring device and optical-fiber-characteristic measuring method

A measurement range is extended while maintaining the spatial resolution high by completely separating the increment of a probe light from noises. Modulations are performed on both probe light and pump light to differentiate both lights. Using the modulations, only the change in the probe light necessary for measuring the characteristic of a measurement-target optical fiber FUT can be separated. Accordingly, unlike the conventional technology, an optical wavelength filter becomes unnecessary. Further, in a case where an amplitude &#x394;f of the frequency modulation of a light sourceis made wide to some extent to make the measurement range wide while maintaining a spatial resolution &#x394;z high, the amplitude &#x394;f does not affect to detection of the change in the probe light. Therefore, the increment of the probe light can be completely separated from noises, thereby extending the measurement range while maintaining the spatial resolution &#x394;z high.

Growing community of inventors

Tokyo, Japan

Kwang Yong Song