Dual wavelength distributed temperature sensing with built-in fiber integrity monitoring

Patent metadata

Field	Value
Publication number	US-11280687-B2
Application number	US-201816119807-A
Country	US
Kind code	B2
Filing date	Aug 31, 2018
Priority date	Aug 31, 2018
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

In some examples, a temperature distribution sensor may include a laser source to emit a laser beam that is tunable to a first wavelength and a second wavelength for injection into a device under test (DUT). A first wavelength optical receiver may convert a return signal corresponding to the first wavelength with respect to Rayleigh backscatter or Raman backscatter Anti-Stokes. A second wavelength optical receiver may convert the return signal corresponding to the second wavelength with respect to Rayleigh backscatter or Raman backscatter Stokes. Bending loss associated with the DUT may be determined by utilizing the Rayleigh backscatter signal corresponding to the first wavelength and the Rayleigh backscatter signal corresponding to the second wavelength. Further, temperature distribution associated with the DUT may be determined by utilizing the Raman backscatter Anti-Stokes signal corresponding to the first wavelength and the Raman backscatter Stokes signal corresponding to the second wavelength.

First claim

What is claimed is:

1. A temperature distribution sensor comprising:
a laser source to emit a laser beam that is tunable to a first wavelength and to a second wavelength for injection into a device under test (DUT);
a first wavelength optical receiver to convert a return signal corresponding to the first wavelength with respect to Rayleigh backscatter and Raman backscatter Anti-Stokes;
a second wavelength optical receiver to convert a return signal corresponding to the second wavelength with respect to Rayleigh backscatter and Raman backscatter Stokes;
a processor; and
a memory storing machine readable instructions that when executed by the processor cause the processor to:
determine bending loss associated with the DUT by utilizing the Rayleigh backscatter signal corresponding to the first wavelength and the Rayleigh backscatter signal corresponding to the second wavelength,

wherein an incident signal associated with the first wavelength generates the Rayleigh backscatter signal corresponding to the first wavelength and the Raman backscatter Stokes signal corresponding to the second wavelength, and an incident signal associated with the second wavelength generates the Rayleigh backscatter signal corresponding to the second wavelength and the Raman backscatter Anti-Stokes signal corresponding to the first wavelength.

2. The temperature distribution sensor according to claim 1 , wherein the machine readable instructions, when executed by the processor, further cause the processor to:
determine temperature distribution associated with the DUT by utilizing the Raman backscatter Anti-Stokes signal corresponding to the first wavelength and the Raman backscatter Stokes signal corresponding to the second wavelength.

3. The temperature distribution sensor according to claim 1 , wherein the DUT includes an optical fiber.

4. The temperature distribution sensor according to claim 1 , wherein the machine readable instructions, when executed by the processor, further cause the processor to:
identify, by combining measurements associated with the Rayleigh backscatter signal and the Raman backscatter Anti-Stokes signal analyzed at the first wavelength, and the Rayleigh backscatter signal and the Raman backscatter Stokes signal analyzed at the second wavelength, a false temperature offset related to an attribute of the DUT.

5. The temperature distribution sensor according to claim 4 , wherein the attribute of the DUT includes the bending loss associated with the DUT.

6. The temperature distribution sensor according to claim 5 , wherein the bending loss associated with the DUT results in a wavelength sensitive loss-event in the DUT, and wherein the machine readable instructions, when executed by the processor, further cause the processor to:
compensate for the wavelength sensitive loss-event in the DUT.

7. The temperature distribution sensor according to claim 6 , wherein the machine readable instructions, when executed by the processor, further cause the processor to:
re-align an associated trace on both sides of the wavelength sensitive loss-event to compensate for the wavelength sensitive loss-event in the DUT.

8. The temperature distribution sensor according to claim 6 , wherein the machine readable instructions, when executed by the processor, further cause the processor to:
perform local differential attenuation correction to compensate for the wave sensitive loss-event in the DUT.

Assignees

• Viavi Solutions Inc

Inventors

• Champavere Andre

Classifications

• G01D5/35361

  using elastic backscattering to detect the measured quantity, e.g. using Rayleigh backscattering · CPC title

• G01K11/3206 Primary

  at discrete locations in the fibre, e.g. using Bragg scattering · CPC title

• G01K1/00

  Details of thermometers not specially adapted for particular types of thermometer (circuits for reducing thermal inertia G01K7/42) · CPC title

• G01K11/32 Primary

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

• G01D5/35364

  using inelastic backscattering to detect the measured quantity, e.g. using Brillouin or Raman backscattering · CPC title