Neubrex Co., Ltd.

Kenichi Nishiguchi

Kinzo Kishida

Che-Hsien Li

Yoshiaki Yamauchi

Yahei Koyamada

Artur Guzik

Atsushi Makita

In a measurement requiring a high space resolution using S-BOTDR, a pulse train composed of a plurality of pulses having the interval between the pulses longer than the phonon lifetime is interpulse-code-modulated. A Golay code is used for the interpulse code modulation to eliminate the sidelobes of the correlation in using a technique of correlation. In a technique without using correlation, an Hadamard matrix is used for the interpulse code modulation and the resultant matrix is inverted in the signal processing.

Brillouin scattering measurement method and Brillouin scattering measurement device

A distributed fiber optic acoustic detection device employs a novel distributed acoustic detection method using a phase noise cancelling distributed acoustic sensing (PNC-DAS) technique.

Distributed fiber optic acoustic detection device

A plurality of optical fibers is helically embedded in tubular installation layers on the outer circumferential surface of a shaped body having a circular cross section. A three-dimensional position of the shaped body after deformed produced by bend, torsion, or stretch due to external force is measured by utilizing frequency change or phase change of pulse laser light emitted into the optical fibers caused by Brillouin scattering and/or Rayleigh scattering occurring in the optical fiber deformed in accordance with the shaped body deformation.

Three-dimensional position measurement system

A distributed optical fiber sound wave detection device is provided with an optical pulse emission unit that causes an optical pulse to be incident into the optical fiber, and a Rayleigh scattered light reception unit that receives Rayleigh scattered light produced inside the optical fiber. The optical pulse emission unit outputs the optical pulse that is modulated using a code sequence which has a predetermined length and by which the optical pulse is divided into a plurality of cells. The Rayleigh scattered light reception unit includes a phase variation derivation unit that performs demodulation corresponding to the modulation in the optical pulse emission unit on the Rayleigh scattered light and determines a phase variation thereof from the demodulated Rayleigh scattered light, and a sound wave detection unit that determines a sound wave that has struck the optical fiber from the phase variation determined by the phase variation derivation unit.

Distributed optical fiber sound wave detection device

The present invention provides a distributed optical fiber sensor capable of measuring the strain and temperature of an object to be measured simultaneously and independently with high spatial resolution. A distributed optical fiber sensor FS is a distributed optical fiber sensor which uses an optical fiberas a sensor, and a strain and temperature detectormeasures a Brillouin frequency shift amount caused by a strain and a temperature generated in the optical fiberby using a Brillouin scattering phenomenon, measures a Rayleigh frequency shift amount caused by the strain and temperature generated in the optical fiberby using a Rayleigh scattering phenomenon, and calculates the strain and temperature generated in the optical fiberfrom the measured Brillouin frequency shift amount and Rayleigh frequency shift amount.

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Kobe, Japan

Kenichi Nishiguchi