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1. WO2020117457 - CAPTEUR DISTRIBUÉ HAUTE RÉSOLUTION UTILISANT UNE FIBRE OPTIQUE À COEUR DÉCALÉ

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

What is claimed is:

1. A distributed sensing system comprising

a contortion-sensing optical fiber having at least one offset core region; and

an optical frequency domain reflectometry (OFDR) system coupled to the contortion-sensing optical fiber.

2. The distributed sensing system as defined in claim 1 wherein

the contortion-sensing optical fiber includes a continuous fiber Bragg grating (FBG) inscribed along the at least one offset cote region, the continuous FBG formed to exhibit a defined Bragg wavelength lb,^ and the system further comprises

a Fourier analyzer coupled to the optical detector and utilized to perform a Fourier transform on the optical detector output signal to generate a measurement of a local Bragg wavelength, wherein a defined shift in wavelength between the defined Bragg wavelength and the local Bragg wavelength corresponds to the application of a force to the contortion-sensing optical fiber.

3. The monitoring system as defined in claim 1 wherein the optical fiber comprises a single offset core displaced at a radius R from a central axis of the optical fiber.

4. The monitoring system as defined in claim 3 wherein R is within the range of approximately 10% - 90% of the outer radius of the optical fiber.

5. The monitoring system as defined in claim 3 wherein the offset core is disposed in a spiral form around the central axis, the spiral being periodic with a defined period Lfw.

6. The monitoring system as defined in claim 1 wherein the optical fiber comprises a plurality of offset cores, each having a same displacement R from a central axis and positioned to exhibit a like separation between adjacent offset cotes.

7. The monitoring system as defined in claim 6 wherein the plurality of offset cores are disposed in a spiral configuration around the central axis, each offset core exhibiting substantially the same spiral periodicity


8. The monitoring system as defined in claim 1 wherein the optical fiber is formed of a glass material.

9. The monitoring system as defined in claim 1 wherein the optical fiber is formed of a polymer material with an elasticity less than the elasticity of glass so as to detect smaller scale force changes than glass fibers.

10. The system as defined in claim 1, further comprising

a reference device disposed adjacent to a length of the contortion-sensing optical fiber, the reference device including a corrugated surface of a defined pattern for creating a contortion in the fiber that can be converted into the applied force

11. The monitoring system as defined in claim 10 wherein the reference device comprises rigid plate with a corrugated surface.

12. The monitoring system as defined in claim 10 wherein the reference device comprises a rigid plate with a corrugated surface; and

a flat plate disposed parallel to, and spaced-apart from, the rigid plate, wherein the contortion-sensing optical fiber is disposed between the rigid plate and the flat plate, with the rigid plate oriented such that the corrugated surface is adjacent to the contortion-sensing optical fiber, a longitudinal axis of the contortion-sensing optical fiber aligned in parallel with the rigid plate and the flat plate.

13. The monitoring system as defined in claim 10 wherein the reference device comprises a pair of plates, each plate having a corrugated surface, wherein the contortion-sensing optical fiber is disposed between the pair of plates with the corrugated surfaces disposed adjacent to the optical fiber.

14. The monitoring system as defined in claim 10 wherein the corrugated surface comprises an aperiodic pattern of corrugations across the extent of the surface.

15. The monitoring system as defined in claim 10 wherein the corrugated surface comprises a periodic pattern of corrugations across the extent of the surface.

16. The monitoring system as defined in claim 15 wherein the periodic pattern of corrugations comprises sinusoidally-varying corrugations of a defined period


17. The monitoring system as defined in claim 10 wherein the contortion-sensing fiber is formed to including a continuous FBG and variation in FBG is created by the reference device.

18. The monitoring system as defined in claim 17 wherein the reference device comprises a pair of plates, each plate having a corrugated surface in the form of periodic corrugations of the same defined period wherein the plates are disposed relative to one another such that the

corrugations align, the contortion-sensing optical fiber disposed between the aligned sets of corrugations such that the application of an external force to the reference device creates local strain within the FBG of the optical fiber related to the period of the corrugations.

19. The monitoring system as defined in claim 17 using a Fourier transform of modulations in the FBG wavelength as created by the reference device to determine the presence of contortions.

20. The monitoring system as defined in claim 10 disposed as a component in a catheter or surgical instrument.