JPWO2020058376A5

JPWO2020058376A5 -

Info

Publication number: JPWO2020058376A5
Application number: JP2021513820A
Authority: JP
Publication date: 2022-09-01
Anticipated expiration: 2039-09-19

Claims

an optical fiber having a plurality of at least four fiber cores embedded therein spaced apart from a central longitudinal axis;
In an optical fiber sensor having
The plurality of fiber cores includes a first subset of at least two fiber cores and a second subset of at least two fiber cores, wherein the first subset of fiber cores and the second subset of fiber cores has one or more fiber Bragg gratings along the length of each fiber core, the second subset of fiber cores configured to provide redundancy in shape sensing measurements of the fiber sensor , the fiber cores of said first subset are azimuthally distributed about said central axis with respect to each other, and each fiber core of said second subset comprises two neighboring fiber cores of said first subset; azimuthally non-equidistant about said central axis with respect to said second subset of fiber cores and disposed between two neighboring fiber cores of said first subset; having an angular position closer to the other of said two neighboring fiber cores of said first subset than to one of said two neighboring fiber cores of one subset;
fiber optic sensor.

the first subset of fiber cores. azimuthally equidistant from each other about said central axis, and wherein the fiber cores of said second subset are azimuthally equidistant from each other about said central axis. Item 1. The optical fiber sensor according to item 1.

a first subset of fiber cores comprising three fiber cores arranged at a radial distance from the central longitudinal axis and a second subset of fiber cores arranged at a radial distance from the central longitudinal axis; The fiber optic sensor of claim 1, comprising three fiber cores.

the angle between the angular position of one fiber core of the second subset in the azimuthal direction about the central axis and the angular position of one of the two neighboring fiber cores of the first subset , at least 10% less than the half angle between the angular positions of the two neighboring fiber cores of the first subset.

The angle between the angular position of one fiber core of the second subset in the azimuthal direction about the central axis and the angular position of one of the two neighboring fiber cores of the first subset is , in the range of 20° to 40°.

the angle between the angular position of one fiber core of the second subset in the azimuthal direction about the central axis and the angular position of one of the two neighboring fiber cores of the first subset, 4. The fiber optic sensor of claim 3, which is about 30[deg.].

2. The fiber optic sensor of claim 1, wherein the optical properties of the fiber cores of the second subset are different than the optical properties of the fiber cores of the first subset.

The first subset of fiber cores has a first resonant wavelength responsive to light introduced into the fiber cores without strain, and the second subset of fiber cores has a first resonant wavelength responsive to light introduced into the fiber cores without strain. 2. The fiber optic sensor of claim 1, having a second resonant wavelength responsive to light introduced into the core, said second resonant wavelength being different than said first resonant wavelength.

The fiber optic sensor of claim 1, wherein the first subset of fiber cores and the second subset of fiber cores have equal distances from the central axis.

The fiber optic sensor of claim 1, wherein said optical fiber core further comprises a central fiber core located on said central axis of said fiber.

An optical shape sensing device comprising an optical fiber sensor according to any one of claims 1-10.

An optical fiber sensor according to any one of claims 1 to 10;
interrogating the first subset of fiber cores and the second subset of fiber cores of the optical fiber sensor with light in a scanning wavelength range; an optical interrogation unit configured to measure a reflectance spectrum received from
an evaluation unit configured to reconstruct the shape of the fiber sensor using the reflection spectrum;
an optical shape sensing system.

The optical interrogation unit is configured to set the scanning wavelength range such that the center wavelength of the scanning wavelength range is decentered with respect to the first resonant wavelength of the fiber cores of the first subset. 13. The optical shape sensing system of claim 12, wherein the resonant wavelength is responsive to light introduced into the fiber cores of the first subset in an unstrained condition of the fiber cores.

The optical interrogation unit is configured to set the scanning wavelength range such that a center wavelength of the scanning wavelength range is decentered with respect to a second resonant wavelength of the fiber cores of the second subset. 13. The optical shape sensing system of claim 12, wherein the second resonant wavelength is responsive to light introduced into the fiber cores of the second subset with no strain on the fiber cores.

providing a fiber optic sensor according to any one of claims 1 to 10;
optically interrogating the first subset of fiber cores and the second subset of fiber cores;
measuring reflection spectra of light returning from the first subset of fiber cores and the second subset of fiber cores;
reconstructing the shape of the fiber optic sensor using the reflectance spectrum;
A method for optical shape sensing, comprising: