Optical fiber temperature distribution measuring device

Patent metadata

Field	Value
Publication number	US-2016018271-A1
Application number	US-201514751365-A
Country	US
Kind code	A1
Filing date	Jun 26, 2015
Priority date	Jul 16, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

An optical fiber temperature distribution measuring device includes: an optical fiber as a sensor; a calculation control unit for measuring a temperature distribution along the optical fiber by using backward Raman scattered light from the optical fiber; a far-end-position dispersion characteristic calculation unit for obtaining a dispersion characteristic of the optical fiber at a far-end position thereof; a per-unit-length dispersion characteristic calculation unit for obtaining a per-unit-length dispersion characteristic of the optical fiber based on the dispersion characteristic of the optical fiber at the far-end position thereof; and a correction parameter calculation unit for calculating a correction parameter for correcting a dispersion characteristic of the optical fiber based on a dispersion characteristic at each of different positions along the optical fiber.

First claim

What is claimed is:

1 . An optical fiber temperature distribution measuring device comprising:
an optical fiber as a sensor; a calculation control unit for measuring a temperature distribution along the optical fiber by using backward Raman scattered light from the optical fiber; a far-end-position dispersion characteristic calculation unit for obtaining a dispersion characteristic of the optical fiber at a far-end position thereof; a per-unit-length dispersion characteristic calculation unit for obtaining a per-unit-length dispersion characteristic of the optical fiber based on the dispersion characteristic of the optical fiber at the far-end position thereof; and a correction parameter calculation unit for calculating a correction parameter for correcting a dispersion characteristic of the optical fiber based on a dispersion characteristic at each of different positions along the optical fiber.

2 . The optical fiber temperature distribution measuring device according to claim 1 , wherein
the correction parameter calculation unit is configured to obtain the correction parameter by performing a convolution calculation of an inverse characteristic of the dispersion characteristic at each of different positions along the optical fiber and an inverse characteristic of a response characteristic of a body of the optical fiber temperature distribution measuring device.

3 . The optical fiber temperature distribution measuring device according to claim 2 , wherein
the correction parameter calculation unit is configured to obtain the dispersion characteristic at each of different positions along the optical fiber and the inverse characteristic thereof from the per-unit-length dispersion characteristic of the optical fiber.

4 . The optical fiber temperature distribution measuring device according to claim 1 , wherein
the far-end-position dispersion characteristic calculation unit is configured to obtain the dispersion characteristic of the optical fiber at the far-end position thereof by convoluting a response characteristic of the optical fiber at the far-end position thereof with an inverse characteristic of a response characteristic of the body of the optical fiber temperature distribution measuring device.

5 . The optical fiber temperature distribution measuring device according to claim 4 , wherein
the calculation control unit is configured to obtain the response characteristic of the optical fiber at the far-end position thereof using a known parameter of the optical fiber.

6 . The optical fiber temperature distribution measuring device according to claim 5 , wherein
the calculation control unit is configured to obtain the response characteristic of the body of the optical fiber temperature distribution measuring device based on a result of a level measurement of the backward Raman scattered light with the optical fiber unconnected to the body of the optical fiber temperature distribution measuring device.

7 . The optical fiber temperature distribution measuring device according to claim 1 , further comprising:
an averaging calculation unit for obtaining a linear value of Stokes light and a linear value of anti-Stokes light by averaging the Stokes light and the anti-Stokes light, respectively, of the backward Raman scattered light; and a spatial resolution calculation unit for performing a calculation of convoluting the correction parameter with the linear value of the Stokes light and the linear value of the anti-Stokes light.

8 . The optical fiber temperature distribution measuring device according to claim 7 , wherein
the far-end-position dispersion characteristic calculation unit is configured to obtain the dispersion characteristic of the optical fiber at the far-end position thereof by performing a first calculation of convoluting a characteristic of a filter for removing a noise component on a high-frequency side with the linear value of the Stokes light and the linear value of the anti-Stokes light, and a second calculation of convoluting an inverse characteristic of the characteristic of the filter and an inverse characteristic of a response characteristic of a body of the optical fiber temperature distribution measuring device with a result obtained by the first calculation.

9 . The optical fiber temperature distribution measuring device according to claim 1 , wherein
the far-end-position dispersion characteristic calculation unit is configured to obtain the dispersion characteristic of the optical fiber at the far-end position thereof by convoluting an inverse characteristic of a characteristic of a filter for removing a noise component on a high-frequency side and an inverse characteristic of a response characteristic of a body of the optical fiber temperature distribution measuring device with a response characteristic of the optical fiber at the far-end position thereof.

Assignees

• Yokogawa Electric Corp

Inventors

• Shida Hideo

Classifications

• G01K2011/324

  Physics · mapped topic

• G01K11/32 Primary

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title

• G01K11/324

  using Raman scattering · CPC title